op chem 1

Question 1

1.’Atomic theory’ of matter was given by (A) Avogadro (B) Dalton (C) Newton (D) Pascal

Answer 1

(B) [SSC MTS Exam. 2014] Exp: Atomic theory of matter was given by John Dalton. According to this theory, matter is made up of extremely small indivisible and indestructible particles called Atoms.

Question 2

2.Atomic size is of the order of— (A) 10-8 cm (B) 10-10 cm (C) 10-13 cm (D) 10-6 cm

Answer 2

(A) Exp: Atomic size is of the order of 10-10 m or 10-8 cm. Atomic size is the distance from the nucleus to the Valence Shell (outermost shell) of an atom.

Question 3

3.The fundamental particles that composed on atom are - (A) Proton, electron, meson (B) Proton, electron, photon (C) Proton, electron, neutron (D) Proton, electron, deuteron

Answer 3

(C) [SSC MTS 2006, SSC CHSL 2013] Exp: All atoms except hydrogen atoms are composed of three fundamental particles, namely electrons, protons and neutrons.

Question 4

4.The size of the nucleus is measured in: (A) amu (B) angstrom (C) cm (D) Fermi

Answer 4

(D) (SSC CGL 2015) Exp: The size of the nucleus is measured in fermi (1 fermi = 10-15m)

Question 5

5.The radius of an atomic nucleus is of the order of— (A) 10-10 cm (B) 10-13 cm (C) 10-15 cm (D) 10-8 cm

Answer 5

(B) Exp: The radius of an atomic nucleus is of the order of 10-15 m or 10-13 cm.

Question 6

6.Nucleus of an atom consists of. (A) Proton (B) Neutron (C) Proton and Neutron (D) Electron, Proton and Neutron

Answer 6

(C) [SSC Section Officer (Audit) 2003] or The fundamental particles present in the nucleus of an atom are (A) Electron, proton (B) Proton, neutron (C) Neutron, electron (D) Neutron, positron (B) [SSC Tax Asst. (Income Tax & Central Excise) 2004] or

Question 7

Which among the following is present inside the nucleus of an atom? (A) Protons and Neutrons (B) Electrons and Protons (C) Neutrons and Electrons (D) Neutrons, Protons, Electrons

Answer 7

(A) (SSC CHSL 2016) Exp: All atoms except hydrogen atom, are composed of three fundamental particles, namely electrons, protons and neutrons. Protons and neutrons are present inside the nucleus.

Question 8

7.Which of the following is not a nucleon? (A) Proton (B) Electron (C) Neutron (D) Positron

Answer 8

(B) [SSC CGL 2013] Exp: In the given options, electron is not a nucleon because it is present in shells, while proton, neutron and positron are present in nucleus.

Question 9

8.According to Rutherford’s atomic model, the electron inside an atom are- (A) Stationary (B) Centralized (C) Non-stationary (D) None of these

Answer 9

(C) (SSC CHSL 2016) Exp: According to Rutherford’s atomic model, the electron inside an atom can not be stationary. The electrostatic attraction between electrons and nucleus gets used up in revolving the electrons around the nucleus.

Question 10

9.Rutherford’s -scattering experiment related to the size of the— (A) Nucleus (B) Atom (C) Electron (D) Neutron

Answer 10

(A) Exp: Rutherford bombarded very thin gold foil with -particle. This is known as Rutherford’s famous -particle scattering experiment. On the basis of experiment Rutherford proposed the nuclear model of atom which explains the size of nucleus.

Question 11

10.Discovery of the nucleus of an atom was due to the experiment carried out by— (A) Bohr (B) Rutherford (C) Moseley (D) Thomson

Answer 11

(B) Exp: Rutherford bombarded very thin gold foil with -particle. This is known as Rutherford’s famous - particle scattering experiment. On the basis of experiment, Rutherford proposed the nuclear model of atom.11. The atomic number of carbon is 6 and its atomic mass is

Question 12

11.How many are there protons in the nucleus of carbon? (A) 6 (B) 12 (C) 18 (D) zero

Answer 12

(A) [SSC CGL Exam. 2002] Exp: Atomic number of carbon is 6. Z = p = e, So, number of protons in carbon atom will be 6.

Question 13

12.When Helium atom loses electron, then it becomes- (A) Proton (B) Positive Helium ion (C) Negative Helium ion (D) Alpha Particle

Answer 13

(B) [SSC CGL Exam, 2015] Exp: When Helium atom loses electron, then it forms positive helium ion. + - He He +e

Question 14

13.Which of the following particle is negatively charged? (A) Proton (B) Neutron (C) Positron (D) Electron

Answer 14

(D) [SSC LDC 2005] Exp: Electron bears -ve charge. Particle Discoverer Mass Charge Proton Goldstein 1.672×10-27 +1.6×10 C -19 Neutron Chadwick 1.674×10 Neutral Positron Anderson 9.1×10 +1.6×10 -19 C Electron Thomson 9.1×10 -1.6×10 C -19 kg -27 kg -31 kg -31 kg

Question 15

14.The absolute value of charge on electron was determined by— (A) J.J. Thomson (B) R.A. Millikan (C) Rutherford (D) Chadwick

Answer 15

(B) Exp: The absolute value of charge on electron was determined by- R.A. Millikan in 1909 by Oil drop method.

Question 16

15.Electrons move around the nucleus in (A) Translatory (B) Spin (C) Orbital (D) Vibrational

Answer 16

(C) Exp: Electrons revolve around the nucleus in circular paths of fixed energy are called stationary states or Orbits.

Question 17

16.An atom has 2 electorns in K-shell, 8 electrons in L-shell and 6 electrons in M - shell. The number of s - electrons present in that element is - (A) 6 (B) 5 (C) 7 (D) 10

Answer 17

(A) [SSC CHSL 2012] Exp: K = 2 electrons L = 8 electrons M = 6 electrons Total = 16 electrons Electronic configuration 1s², 2s² 2p6, 3s² 3p4 Total No. of s electrons = 6

Question 18

17.The proton is heavier than an electron by (A) 187 times (B) 1837 times (C) 3837 times (D) 2827 times

Answer 18

(B) Exp: mp = 1.0072766 amu me = 0.000549 amu Comparative mass of proton is 1837 times heavier than an electron.

Question 19

18.CN- ion is isoelectronic with - (A) N2 (B) CO (C) both a & b (D) None

Answer 19

(C) Exp: Isoelectronic species have same no. of electrons. C = 6 N = 7 O = 8 CN = 6 + 7 + 1 = 14 N = 7 + 7 = 14 CO = 6 + 8 = 14 - 2

Question 20

19.Which of the following is the maximum number of electrons that can be present in M-shell? (A) 2 (B) 8 (C) 18 (D) 32

Answer 20

(C) [SSC DP SI Exam 2014] Exp: Maximum number of electrons in a given shell = 2n2 Where n represents number of shell. Value of n = 1, 2, 3 …………. So, maximum number of electrons in M (3rd) shell = 2×32=18

Question 21

20.Which among the following will be a negative ion? (A) If it has more electrons than protons (B) If it has more electrons than neutrons (C) If it has more protons than electrons (D) If it has more protons than neutrons

Answer 21

(A) (SSC CHSL 2016) Exp: For electrically neutral z = p = e for positive ion (cation), Z = p > e for negative ion (Anion), Z = p < e positive ion is formed after removal of electrons while negative ion is formed by gaining of electrons.

Question 22

21.Electrons in the highest energy level of an atom are called ________. (A) Valence protons (B) Orbital protons (C) Valence electrons (D) Orbital electrons

Answer 22

(C) (SSC CHSL 2016) Exp: Electrons in the highest energy level of an atom are called Valence electrons or outermost shell electrons. Only these electrons participate in chemical bond formation.

Question 23

22.Fe has 26 protons in its nucleus. What are the number of electrons in Fe2+ (II) ion? (A) 24 (B) 26 (C) 28 (D) 13

Answer 23

(A) (SSC CHSL 2016) Exp: We know that for an atom z = p = e for cation z = p > e Iron (Fe) has 26 protons in its nucleus so it has also 26 electrons. But in Fe2+ ion, iron has 2 less electrons so it has 24 electrons.

Question 24

23.Number of p-electrons in bromine atom: (A) 12 (B) 15 (C) 7 (D) 17

Answer 24

(D) Exp: Electronic Configuration of Bromine:- 35Br- 2, 8, 18, 7 1s2, 2s22p6, 3s2 3p63d10, 4s24p5 Total no. of p electrons:- 2p6 = 6 3p6 = 6 5 4 5 p 17

Question 25

24.Which of the following has maximum Mass? (A) Electron (B) Proton (C) Neutron (D) Nucleus of Hydrogen

Answer 25

(C) [SSC CGL 2013] Exp: Amu = Atomic Mass Unit Atomic mass unit is defined as the Quantity of element is equal to 1/12 of the mass of an atom of carbon (C12). Mass of the following is given as. Electron = 0.000549 (amu) Proton = 1.00728 (amu) Neutron = 1.00867 (amu) Nucleus of Hydrogen = 1.00783 (amu) So neutron has maximum mass.

Question 26

25.The mass of proton and mass of _____ is same. (A) Neutron (B) Electron (C) Isoprone (D) Alpha particle

Answer 26

(A) Exp: Mass of proton & mass of neutron is same. Mass of the following is given as. Electron = 0.000549 (amu) Proton = 1.00728 (amu) Neutron = 1.00867 (amu)

Question 27

26.The nuclear particle having no mass and no charge, but only spin is (A) Proton (B) Neutrino (C) Meson (D) Electron

Answer 27

(B) [SSC CGL Exam. 2013] Exp: The neutrino is so named because it is electrically neutral. It has very small mass & charge. It has spin only.

Question 28

27.Who is awarded by Nob le prize for the discovery of Neutron? (A) Chadwick (B) Rutherford (C) Neil Bohr (D) Roentgen

Answer 28

(A) [SSC LDC 2005] Exp: Neutron is discovered by J. Chadwick in 1932 by Beryllium with -particle that he is awarded by Nobel prize. Neutron is a Neutral particle. 9 4Be + 4 2He 12 6C + 1 0 n Beryllium -particle Carbon Neutron

Question 29

28.The electronic configuration of a dipositive ion M²+ is 2, 8, 14 and its atomic mass is 56. The number of neutrons in the nucleus would be: (A) 30 (B) 32 (C) 34 (D) 42

Answer 29

(A) Exp: M2+ = 2, 8, 14 As metal is dipositive Z = 2 + 8 + 14 + 2 = 26 n = A - Z = 56 - 26 = 30 where n = no. of neutrons Z = Atomic No. A = Mass No.

Question 30

29.The triad of nuclei is isotone in: (A) 6C14, 7N15, 9F17 (B) 6C12, 7N14, 9F18 (C) 6C14, 7N14, 9F17 (D) 6C14, 7N14, 9F19

Answer 30

(A) Exp: Since 6C14, 7N15 and 9F17 have the same number of neutrons equal to 8 (14 - 6 = 8, 15 - 7 = 8, 17 - 9 = 8), these nuclei are isotonic with each other.

Question 31

30. The unrelated member of the following group is (A) Helium ion (B) Neutron (C) Proton (D) Cyclotron

Answer 31

(D) Exp: Cyclotron is a type of particle accelerator invented by Ernest Lawrance. It is used to accelerate charged particles to high energies.

Question 32

30.The antiparticle of an electron is (A) Positron (B) Proton (C) Alpha particle (D) Beta particle

Answer 32

(A) [SSC CGL Exam. 2016] Exp: Antiparticle of an electron is positron because it has same mass and charge (but opposite sign) like an electron.

Question 33

31.Which two basic forces are able to provide an attractive force between two neutrons? (A) Gravitational and Electrostatic forces (B) Some other forces (C) Gravitational and Nuclear forces (D) Electrostatic and Nuclear forces

Answer 33

(C) [SSC CHSL 2012] Exp: Gravitational and nuclear forces are able to provide an attractive force between two neutrons. However, nuclear forces are stronger than gravitational forces. Nuclear forces also act between neutron-proton and proton-proton.

Question 34

32.Cathode rays are- (A) Stream of a-particles (B) Stream of electrons (C) Electromagnetic waves (D) Radiations

Answer 34

(B) [SSC Stenographer 2012] Exp: A Cathode Ray is a beam of electrons in a vacuum tube travelling from the negatively charge electrode (Cathode) at one end to the positively charged electrode (anode) at the other, across a voltage difference between the electrodes. They are also called Electron Beams.

Question 35

33.When cathode rays strike a target of high atomic weight, they give rise to (A) a-rays (B) b and g rays (C) X-rays (D) Positive rays

Answer 35

(C) [SSC CGL Re-Exam. 2013] Exp: When cathode rays strike a solid target of high atomic weight and high melting point such as molybdenum tungsten, etc they give rise to a highly penetrating radiations called the X-rays.

Question 36

34.J.J. Thomson proposed a model which is generally called ……….. model. (A) Cream and cake (B) Plum and pudding (C) Plum and cake (D) Cream and pudding

Answer 36

(B) [SSC CPO Exam. 2016] Exp: J.J. Thomson proposed that an atom possesses a spherical shape in which the positive charge is uniformly distributed. The electrons are embedded into it. This model is known is plum pudding, raisin pudding or watermelon Model.

Question 37

35.Match column-I and column-II Column-I Column-II A. Thomson model 1. Dual nature of electron B. Rutherford model 2. Nuclear theory C. Bohr’s model 3. Plum pudding model D. De-Broglie theory 4. Concept of quantization of energy (A) A-3, B-4, C-2, D-1 (B) A-2, B-4, C-1, D-2 (C) A-2, B-1, C-3, D-4 (D) A-3, B-2, C-4, D-1

Answer 37

(D) Exp: A. Thomson Model Plum Pudding Model B. Rutherford Model Nuclear theory C. Bohr’s Model Concept of quantization of energy D. De-Broglie theory Dual Nature of Electron

Question 38

36.Atomic number of an atom gives the number of which of the following? (A) Electrons (B) Protons (C) Neutrons (D) Neutrons and Protons

Answer 38

(B) [SSC CHSL Exam. 2016] Exp: Atomic number is equal to number of protons present in nucleus. It is a characteristic of a chemical element.

Question 39

37.Which of the properties of the element is a whole number? (A) Atomic mass (B) Atomic number (C) Atomic radii (D) Atomic volume

Answer 39

(B) Exp: Atomic number is a whole number because it is equal to number of protons present in nucleus.

Question 40

38.Element having atomic number 29 is related to - (A) s-Block (B) d-Block (C) p-Block (D) f-Block

Answer 40

(B) [SSC CGL 2013] Exp: d block elements have electronic configuration (n-1)d1-10 ns0-2. Cu is d block element because it has following electronic configuration 1s2, 2s22p6, 3s23p63d10, 4s1

Question 41

39.Electronic configuration of calcium atom can be written as: (A) [Ne], 4p2 (B) [Ar], 4s2 (C) [Ne], 4s2 (D) [Kr], 4p2

Answer 41

(B) Exp: Electronic configuration of calcium atom:- Ca = 2, 8, 8, 2 Electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s2 Ar = 2, 8, 8 (Z = 18)

Question 42

40.The electronic configuration of chromium (Z =24) is (A) [Ne] 3s23p63d4, 4s2 (B) [Ne] 3s23p63d5, 4s1 (C) [Ne] 3s23p63d1, 4s2 (D) [Ne] 3s23p6, 4s24p4

Answer 42

(B) (SSC CHSL 2016) Exp: Cr (Z = 24) - 2, 8, 13, 1 [Ne] 3s2 3p6 3d5, 4s1 Half filled orbitals are more stable than partially filled orbitals.

Question 43

41.Two elements X and Y are isotonic having atomic weight 54 and 56 respectively. If the atomic number of X is 26, then the atomic number of Y is: (A) 26 (B) 27 (C) 28 (D) 30

Answer 43

Ans (C) Exp: Isotones are the atoms in which the number of neutrons i.e., (A - Z) are equal. Thus if x is the atomic number of Y, then for 26X54 and x Y56 we have: 54 - 26 = 56 - x, x = 28

Question 44

42.What is the formula of potassium ion in the noble state? (A) K+ (B) K2+ (C) K2- (D) K-

Answer 44

(A) (SSC CHSL 2016) Exp: 19K - 2, 8, 8, 1 Noble state means 8 electrons in valence shell. After removal of 1 electron K change into K+ ion. K+ - 2, 8, 8

Question 45

43.Atomic Number of Hydrogen is _______. (A) 4 (B) 3 (C) 2 (D) 1

Answer 45

(D) (SSC CHSL 2016) Exp: Atomic number of hydrogen (1H1) is 1. It has three isotopes name as protium (1H1), deuterium (1H2) and tritium (1H3).

Question 46

44.Atomic number of which of the following elements is greater than that of Magnesium (A) Neon (B) Fluorine (C) Sodium (D) Aluminium

Answer 46

(D) (SSC CHSL 2016) Exp: Atomic number of Aluminium (Z =13) is greater than that of Magnesium (Z =12). Element Atomic numbers (Z) Neon (Ne) = 10 Fluorine (F) = 9 Sodium (Na) = 11 Aluminium (Al) = 13

Question 47

45.Atomic number of which of the following elements is greater than that of Aluminium? (A) Phosphorous (B) Neon (C) Magnesium (D) Sodium

Answer 47

(A) (SSC CHSL 2016) Exp: Atomic number of Phosphorous (Z =15) is greater than that of Aluminium (Z =13). Element Atomic numbers (Z) Phosphorous(P) 15 Neon(Ne) 10 Magnesium(Mg) 12 Sodium(Na) 11

Question 48

46.Atomic number of which of the following elements is greater than that of Phosphorous? (A) Aluminium (B) Silicon (C) Chlorine (D) Magnesium

Answer 48

(C) (SSC CHSL 2016) Exp: Chlorine (Z=17) has higher atomic no than that of phosphorous (Z = 15). Element Atomic numbers (Z) Phosphorous (P) 15 Aluminium (Al) 13 Silicon(Si) 14 Chlorine (Cl) 17 Magnesium(Mg) 12

Question 49

47.Atomic number of which of the following elements is greater than that of Neon? (A) Oxygen (B) Magnesium (C) Nitrogen (D) Boron

Answer 49

(B) (SSC CHSL 2016) Exp: Magnesium (Z =12) has greater atomic no. than that of Neon (Z = 10). Element Atomic numbers (Z) Neon (Ne) 10 Oxygen (O) 8 Magnesium (Mg) 12 Nitrogen (N) 7 Boron(B) 5

Question 50

48.Atomic number of which of the following elements is greater than that of silicon ______ (A) Aluminium (B) Sulphur (C) Magnesium (D) Sodium

Answer 50

(B) (SSC CHSL 2016) Exp: Atomic No. of Sulphur (Z = 16) is greater than that of silicon (Z = 14). Element Atomic numbers (Z) Silicon (Si) 14 Aluminium (Al) 13 Sulphur (S) 16 Magnesium(Mg) 12 Sodium(Na) 11

Question 51

49.Atomic number of which of the following elements is greater than that of Zinc (A) Copper (B) Iron (C) Chromium (D) Bromine

Answer 51

(D) (SSC CHSL 2016) Exp: Atomic number of Bromine (Z = 35) is greater than that of Zinc (Z = 30). Element Atomic numbers (Z) Zinc (Zn) 30 Copper (Cu) 29 Iron(Fe) 26 Chromium (Cr) 24 Bromine (Br) 35

Question 52

50.Atomic number of which of the following elements is greater than that of Iodine (A) Silver (B) Bromine (C) Platinum (D) Zinc

Answer 52

(C) (SSC CHSL 2016) Exp: Atomic number of Platinum (Z = 78) is greater than that of Iodine (Z = 53). Element Atomic numbers (Z) Iodine(I) 53 Silver (Ag) 47 Bromine(Br) 35 Platinum(Pt) 78 Zinc (Zn) 30

Question 53

51.Atomic number of which of the following elements is greater than the of potassium. (A) Sulphur (B) Chlorine (C) Calcium (D) Argon

Answer 53

(C) (SSC CHSL 2016) Exp: Calcium (Z = 20) has higher atomic no. than that of potassium (Z = 19).

Question 54

52.Atomic number of which of the following elements is greater than that of Calcium? (A) Chlorine (B) Argon (C) Sulphur (D) Scandium

Answer 54

(D) (SSC CHSL 2016) Exp: Scandium (Z = 21) has greater atomic no. than that of Calcium (Z = 20). Element Atomic numbers (Z) Sulphur (S) 16 Chlorine(Cl) 17 Calcium (Ca) 20 Argon(Ar) 18 Potassium(K) 19

Question 55

53.Atomic number of which of the following elements is greater than that of Chlorine (A) Potassium (B) Sulphur (C) Aluminium (D) Phosphorous

Answer 55

(A) (SSC CHSL 2016) Exp: Potassium (Z = 19) has higher atomic no. than that of Chlorine (Z = 17).

Question 56

54.Atomic number of which of the following elements is greater than that of Copper? (A) Iron (B) Chromium (C) Zinc (D) Manganese

Answer 56

(C) (SSC CHSL 2016) Exp: Zinc (Z = 30) has higher atomic no. than that of Copper (Z = 29). Element Atomic numbers (Z) Iron(Fe) 26 Chromium(Cr) 24 Zinc (Zn) 30 Manganese (Mn) 25

Question 57

55.Atomic number of an atom gives the number of which of the following? (A) Electrons (B) Protons (C) Neutrons (D) Neutrons and protons

Answer 57

(B) (SSC CGL 2016) Exp: Atomic No. (Z) is numerically equal to the number of protons present in the nucleus of an atom. Thus, Atomic Number (Z) = number of protons.

Question 58

56.Atomic number of which of the following elements is greater than that of Fluorine? (A) Sodium (B) Beryllium (C) Nitrogen (D) Boron

Answer 58

(A) (SSC CHSL 2016) Exp: Atomic Number of Sodium (Z = 11) is greater than that of Fluorine (Z = 9).

Question 59

57.Atomic number of which of the following elements is greater than that of Iron? (A) Manganese (B) Cobalt (C) Calcium (D) Chromium

Answer 59

(B) (SSC CHSL 2016) Exp: Atomic number of Cobalt (Z = 27) is greater than that of Iron (Z = 26).

Question 60

58.Mass number is the sum of - (A) Electrons and Protons (B) Protons and Neutrons (C) Electrons and Neutrons (D) Only Protons

Answer 60

(B) [SSC CHSL 2015] Exp: Mass number (A) = number of protons (p) + number of neutrons (n). A = p + n or Z + n ( p = Z)

Question 61

59.The mass number of an atom is- (A) Always less than its atomic number (B) Always more than its atomic number (C) Always equal to its atomic number (D) Sometimes more and sometimes equal to its atomic number

Answer 61

(D) [SSC CHSL 2010] Exp: The mass number of an atom is equal to sum of number of neutrons and number of protons present in it, which is sometimes more or sometimes equal to its atomic number.

Question 62

60.An Element has Atomic number 17 and Mass number 36, then number of neutrons present in it- (A) 17 (B) 19 (C) 36 (D) 53

Answer 62

(B) [SSC MTS 2008] Exp: A = 36, Z = 17 A = p + n So, n = A - p n = A - Z (Z = p) n = 36 - 17 = 19

Question 63

61.Which of the following element has relative atomic weight that is made up to atom containing each of 17 protons, 18 Neutrons and 17 Electrons? (A) 52 (B) 35 (C) 18 (D) 17

Answer 63

(B) [SSC Stenographer 2005] Exp: Atomic weight = Atomic number (No of Protons) + No of neutrons, 18+17 = 35.

Question 64

62.How many neutrons are there in 92U238 atom? (A) 92 (B) 238 (C) 146 (D) 330

Answer 64

(C) [SSC DP SI Exam. 2014] Exp: Z = p = 92 A = 238 n = A - p = 238 - 92 = 146

Question 65

64. The number of neutrons present in an element having mass number 226 and atomic number 88 is: (A) 88 (B) 138 (C) 314 (D) 50

Answer 65

(B) [SSC Combined Matric Level Exam. 2006] Exp: Z = 88, A = 226 Z = p = e = 88 n = A - p = 226 - 88 = 138

Question 66

65.Atomic mass of Oxygen is 16 and atomic number is 8. What is the mass in grams of 2 moles of oxygen gas? (A) 8 (B) 64 (C) 32 (D) 16

Answer 66

(B) (SSC CHSL 2016) Exp: Molar mass = 2 × 16 = 32 g. No. of moles = 2 Mass of 2 moles = 2 × 32 = 64 gm

Question 67

66.The photoelectric effect is described as the ejection of electrons from the surface of a metal when— (A) It is heated (B) It is placed in strong electric field(C) Electrons of suitable velocity impings on it (D) Light of suitable frequency falls on it

Answer 67

(D) [SSC CGL 2013] Exp: The phenomenon of ejection of electrons from the surface of a metal when light of suitable frequency strikes on it. This phenomenon is known as Photoelectric effect. The emitted electrons are called photoelectrons. Cesium (Cs), Rubidium (Rb) & Potassium (K) shows Photo electric effect.

Question 68

67.The photoelectric emission from metal surface starts only when the incident light has a certain minimum (A) Wavelength (B) Velocity (C) Frequency (D) Acceleration

Answer 68

(C) Exp: Threshold frequency (v0): It is defined as for each metal, certain minimum frequency of light is needed to eject the electrons from the metal surface.

Question 69

68.Propagation of light quanta may be described by- (A) Photons (B) Protons (C) Neutrons (D) Electrons

Answer 69

(A) Exp: Quanta are described as discrete packets of energy. In terms of light quantum is known as Photon.

Question 70

69. The value of planck’s constant is— (A) 6.62×10-34 J (B) 6.62×10-34 J.s (C) 6.62×10-34 erg.s (D) None of these

Answer 70

(B) Exp: Planck’s constant is represented by h. h = 6.62×10-34 J.s

Question 71

69.If an electron and a photon have the same wavelength, then they will have the same (A) Velocity (B) Linear momentum (C) Angular momentum(D) Energy

Answer 71

(B) (SSC CGL 2016) Exp: E = h E = hc …. (i) c E = mc2…. (ii) hc = mc2 = h h mc p 1 p

Question 72

70.Which of the following particle has the dual nature of particle and wave? (A) Neutron (B) Electron (C) Meson (D) Proton

Answer 72

(B) [SSC CGL 2015] Exp: De Broglie predicted that small particles such as electrons should show wave like properties along with particle character. The wavelength () associated with a particle of mass m and moving velocity v is given in the relationship. represents wave nature & p represents particle nature. = h h p mv p mv h = Planck’s constant p = Momentum m = Mass v = Velocity

Question 73

71.The concept of dual nature of radiation was proposed by— (A) Max planck (B) De-Broglie (C) Heisenberg (D) Pauling

Answer 73

(B) Exp: De Broglie predicted that small particles such as electrons should show wave like properties along with particle character. The wavelength () associated with a particle of mass m and moving velocity v is given in the relationship. represents wave nature & p represents particle nature. = h h p mv p mv h = Planks constant p = Momentum m = Mass v = Velocity

Question 74

“72.”“The position and velocity of a small particle like electron can not be simaltaneously determined.”“This statement is— (A) Heisenberg uncertainty principle (B) Pauli’s exclusion principle (C) Aufbau principle (D) De-broglie wave nature of electron”

Answer 74

(A) Exp: P. x > 4 h π P = mv m v. x > 4 h π v. x > 4 h πm P = change in momentum x = change in position v = change in velocity

Question 75

73.Who discovered X- Ray? (A) Wilhelm Roentgen (B) William Lee (C) X Lollswick (D) I Thompson

Answer 75

(A) Exp: X-rays was discovered by Wilhelm Roentgen.

Question 76

By which one of the following, an old written material which can not be read easily, can be read? (A) - rays (B) X - rays (C) IR - rays (D) Radio frequency waves

Answer 76

(B) Exp: X-Rays are used to read an old written material because they have high penetrating power. Uses of X-rays: Detection of abnormalities of the skeletal system. To detect structural deficits or cracks in metal objects. To reveal stress related changes in building materials. In examination of baggage in airports.

Question 77

76.Which one of the following is the correct sequence of wavelength of radiations? (A) UV > Green > IR > Hard X - rays (B) IR > Green > UV > Hard X - rays (C) UV > Hard X - rays > IR > Green (D) IR > Hard X - rays > Green > UV

Answer 77

(B) Exp: Increasing order of wavelength of Electromagnetic Radiations:- Cosmic rays < Gamma rays < X-rays < U.V. rays < Visible radiation < I.R. < Microwaves < Radio waves Note: Wavelength is inversely proportional to frequency.

Question 78

77.Which of the following is not Electromagnetic in nature? (A) Cathode rays (B) X - rays (C) Gamma - rays (D) Infrared - rays

Answer 78

(A) Exp: In the given options, cathode rays are not electromagnetic in nature. Electromagnetic waves are waves which can travel through the vacuum of outer space. They travel with the speed of light. These are Radio waves, Micro-waves, X-rays, Gamma Rays, Infra-Red waves etc.

Question 79

78.Wavelength of which of the following colours of the visible spectrum of light are maximum absorbed by green plants - (A) Green and yellow (B) Red and blue (C) Green and red (D) Blue and yellow

Answer 79

(B) Exp: Chlorophyll is present in leaves. Chlorophyll absorbs light in the red (Long wavelength) and the blue (short wavelength) region of the visible light spectrum.

Question 80

79.Which of the following is not true about X rays? (A) Low power (B) Travel with the speed of light (C) Refracted (D) Can affect photographic plates

Answer 80

(A) (SSC CGL 2016) Exp: The penetrating power of X-Rays is determined by the peak energy (KVp) of the voltage placed across the X-Ray tube. The higher the energy the greater the penetrating power.

Question 81

80.The reverse effect of X-ray emission is (A) Raman effect (B) Compton effect (C) Zeeman effect (D) Photo-electric effect

Answer 81

(D) (SSC CGL 2016) Exp: The production of X-ray is a reverse process of photoelectric effect. In photoelectric effect, Photons are incident on a metal surface and electrons are produced and X-rays are produced when target metal is bombarded by electrons.

Question 82

81.Which of the following has the lowest frequency? (A) Visible light (B) Gamma rays (C) X-rays (D) Ultra violet rays

Answer 82

(A) (SSC CGL 2016) Exp: The different type of radiations are arranged in the decreasing order of frequencies or Increasing order of wavelength as: Cosmic rays, Gamma rays, X-rays, Ultraviolet radiations, Visible radiations, Infrared radiations, Microwaves and Radio waves.

Question 83

82.All isotopes of the same element have — (A) Different atomic numbers and different atomic mass (B) Different atomic numbers and the same atomic mass (C) The same atomic number but different atomic mass (D) The same atomic number and the same atomic mass

Answer 83

(C) [SSC CGL Exam. 2016] Exp: Atoms of an element having same atomic number but having different mass number are known as isotopes. eg:- 1H1, 1H2, 1H3

Question 84

83.Nuclides have same atomic number are called: (A) Isotopes (B) Isobar (C) Isotones (D) Isoelectrons

Answer 84

(A) [SSC MTS 2013] Exp: Nuclides having same atomic number are known as Isotopes. eg:- 7N14 7N15

Question 85

84.Atoms of same element having different mass numbers are called — (A) Isobars (B) Isotopes (C) Isotones (D) Isomers

Answer 85

(B) (SSC CGL 2016) Exp: Atoms of an element having same atomic number but having different mass number are known as isotopes. eg:- 6C12, 6C14

Question 86

85.Chemical properties of isotopes (A) Must be Same (B) Must be Different (C) Need not be Same (D) Need not be Different

Answer 86

(A) [SSC CGL Exam. 2016] Exp: Chemical properties depend on number of valence electrons. Isotopes have same number of electrons. So they have same chemical properties.

Question 87

86.Atoms having the same number of protons but different number of neutrons are called: (A) Isotopes (B) Cations (C) Higgs-boson (D) Anions

Answer 87

(A) [SSC CHSL Exam. 2015] Exp: Atoms having the same number of protons but different number of neutrons are called isotopes.

Question 88

87.Atoms of different elements have (A) Same atomic number and same electronic configuration (B) Different atomic number and same electronic configuration (C) Different atomic number and different number of valence electrons (D) Same number of electrons and neutrons

Answer 88

(C) [SSC CGL Re-Exam. 2013] Exp: Atoms of different elements have different atomic number and different number of valence electrons.

Question 89

88.Atoms having same no of neutron but different no of electrons or protons are called- (A) Isotopes (B) Isobars (C) Isotones (D) Allotropes

Answer 89

(C) [SSC Stenographer 2005] Exp: Atoms having equal number of neutrons but different number of Electron or Protons are called Isotones. For Example 14Si30 15P31 A = 30 31 Z = p = e = 14 15 n = A - p = 16 16

Question 90

89.40Ar18 40K19 40Ca20 are called - (A) Isotones (B) Isotopes (C) Isobars (D) None

Answer 90

(C) [Expected Question] Exp: All have same mass no. but different atomic no. so they are known as Isobars.

Question 91

90.Isobars have - (A) Same mass numbers but different atomic numbers (B) Different mass numbers but same atomic numbers (C) Same mass and atomic numbers (D) Different mass and atomic numbers

Answer 91

(A) (SSC CHSL 2016) Exp: Isobars have same mass number but different atomic number. Eg: 14 6C, 14 7N

Question 92

91.Who was the first to explain hydrogen spectrum? (A) Dalton (B) Neil Bohr (C) Rutherford (D) J.J. Thomson

Answer 92

(B) Exp: Neil Bohr was the first to explain Hydrogen spectrum there are five series in Hydrogen spectrum. 1. Lyman series Ultraviolet region 2. Balmer Series Visible region 3. Paschen Series Infrared region 4. Brackett Series Infrared region 5. Pfund Series Infrared region

Question 93

92.Bohr’s model can explain: (A) Spectrum of hydrogen atom only (B) Spectrum of any atom or ion having one electron only (C) Spectrum of hydrogen molecule (D) Solar spectrum

Answer 93

(B) Exp: Bohr’s model can explain spectrum of any atom or ion having one electron only. eg:- He+, Li2+

Question 94

93. The value of Bohr radius of hydrogen atom is (A) 0.529 × 10-7 cm (B) 0.529 × 10-8 cm (C) 0.529 × 10-9 cm (D) 0.529 × 10-10 cm

Answer 94

(B) Exp: 0.529n2, n = 1, radius is in 10-8 cm. The value of Bohr radius of hydrogen atom is 0.529 × 10-8 cm

Question 95

93.If r is the radius of first orbit, the radius of nth orbit of the hydrogen atom will be: (A) rn2 (B) rn (C) r/n (D) r2n2

Answer 95

(A) Exp: Radius of nth orbit of hydrogen atom rn = r × n2

Question 96

94.When a metal is heated in a flame, the electrons absorb energy and jump to higher energy state. On coming back to the lower energy state, they emit light, which we can observe in (A) Raman spectra (B) Absorption spectra (C) Emission spectra (D) Fluoroscence

Answer 96

(C) [SSC CGL Exam. 2013] Exp: Emission spectra- It is obtained from the substances which emit light on excitation, i.e. either by heating substances on a flame or by passing electric discharge through gases at low pressure or by passing electric current through a thin filament of high melting point metal.

Question 97

95.Bohr’s concept of the orbit in an atom was contradicted by (A) De-broglie relationship (B) Uncertainty principle (C) Plancks hypothesis (D) Hunds rule

Answer 97

(B) Exp: According to Heisenberg’s Uncertainty principle, position & velocity of an object can not be measured simultaneously with accuracy which is in contradict to Bohr’s theory.

Question 98

96.The total energy of revolving electron in an atom (A) Cannot be negative (B) Can have any value above zero (C) Can never be positive (D) Will always be positive

Answer 98

(C) [SSC CHSL Exam. 2010] Exp: Potential energy of the electron is negative inside any atom. The electron also has Kinetic energy which can never be -ve because in expression, there is square of velocity i.e. always +ve & it is smaller in magnitude than the magnitude of potential energy. Total energy = Kinetic energy + Potential energy = 2 1 KZe mv - 2 2 r So, total energy of electron can never be positive.

Question 99

97.The spectrum of helium is expected to be similar to that of: (A) H (B) Na (C) He+ (D) Li+

Answer 99

(D) Exp: He and Li+ both have same number of electron so spectrum of He will be similar to Li+

Question 100

98.When an electron drops from a higher energy level to a low energy level then: (A) Energy is absorbed (B) Energy is emitted (C) Atomic number increases (D) Atomic number decreases

Answer 100

(B) Exp: If energy is absorbed, electrons goes to higher energy level from lower energy level. If energy is released, electronsdrop from a higher energy level to a lower energy level

Question 101

99.In Lyman series an electron jumps from higher energy level to (A) K energy level (B) M energy level (C) N energy level (D) L energy level

Answer 101

(A) Exp: When electron returns to any of the lower energy levels, it emits energy. Lyman series is formed when the electron returns to the lowest energy state (K energy level) from high energy levels.

Question 102

100.In which region of electromagnetic spectrum does the Lyman series of hydrogen atom lie? (A) X-Ray (B) Ultraviolet Ray (C) Visible (D) Infrared

Answer 102

(B) Exp: Spectral lines for Hydrogen atomSeries Spectral region Lyman Ultraviolet Balmer Visible Paschen Infrared Brackett Infrared Pfund Infrared

Question 103

101.The total number of orbitals in a principal shell are: (A) n (B) n² (C) 2n² (D) 3n²

Answer 103

(B) (SSC CHSL 2016) Exp: The total number of orbitals in a principal shell are n².

Question 104

102.The mercury and sodium street lamps light up because of- (A) Atomic absorption (B) Electron absorption (C) Atomic emission (D) Electron emission

Answer 104

(C) [SSC CGL 2015] Exp: The mercury and sodium street lamps light up because of Atomic emission. Atomic emission occurs when a valence electron in a higher energy atomic orbital returns to a lower energy atomic orbital.

Question 105

103.The atomic orbital is— (A) The Circular path of the electron (B) Elliptical shaped orbit (C) Three dimensional field around nucleus (D) The region in which there is maximum probability of finding electron

Answer 105

(D) Exp: The space or a three-dimensional region around the nucleus where there is maximum probability of finding an electron of a specific energy is called an atomic orbital.

Question 106

104.Which of the following atoms has a nonspherical outermost orbital. (A) H (B) Li (C) Be (D) B

Answer 106

(D) Exp: H= 1s1 Li = 1s2, 2s1 Be = 1s2, 2s2, B = 1s2, 2s2,2p1 S-orbital - P-orbital- Spherical dumb-bell shape

Question 107

105.Orientation of atomic orbital is controlled by - (A) Principal Quantum number (B) Magnetic Quantum number (C) Electron spin quantum number (D) Azimuthal Quantum number

Answer 107

(B) [SSC MTS 2013] Exp: Principal Quantum number describes the shell, size of orbital and energy of orbital. Magnetic Quantum number describes the orientation of orbital. Electron spin quantum number describes the orientation of the spin of electron. Azimuthal Quantum number describes the three-dimensional shape of orbital.

Question 108

106.Two electrons in an orbital are differentiated by which of the following? (A) Magnetic quantum number (B) Spin quantum number (C) Principal quantum number (D) Azimuthal quantum number

Answer 108

(B) [SSC CGL Exam. 2016] Exp: = +1/2 one electron of orbital is clockwise and other electron of s-orbital is anticlockwise =-1/2

Question 109

“107.”“All the four quantum numbers of two electrons in an atom are not the same.”” It is the law of — (A) Hund’s rule (B) Pauli’s exclusion principle (C) Uncertainty Principle of Heisenberg (D) Avogadro’s Law”

Answer 109

(B) [SSC Section Officer (Audit) 1997] or

Question 110

108. In a given atom, no two electrons can have the same value for all the four quantum number. This is called— (A) Hund’s rule (B) Pauli’s exclusion principle (C) Uncertainty principle (D) Aufbau principle

Answer 110

(B) Exp: According to Pauli’s exclusion principle - No two electrons in an atom can have the same set of four quantum numbers. or Only two electrons may exist in the same orbital and these electrons must have opposite spin.

Question 111

109.When there are two electrons in the same orbital, they have: (A) Same spin (B) Opposite spin (C) Same or opposite spin (D) No spin

Answer 111

(B) [SSC CGL 2002] Exp: According to Pauli’s exclusion principle only two elctrons may exist in the same orbital and these electrons must have opposite spin.

Question 112

110.Which orbital is dumb- bell shaped? (A) s-orbital (B) p-orbital (C) d-orbital (D) f-orbital

Answer 112

(B) Exp: Orbital Shape s Spherical p dumb bell d double dumb bell f diffused shape

Question 113

111. In an atom the order of filling up of the orbitals is governed by— (A) Aufbau principle (B) Heisenberg’s uncertainty principle (C) Hund’s rule (D) Pauli’s exclusion Principle

Answer 113

(A) Exp: According to Aufbau principle in the ground state of the atoms, the orbitals are filled in order of their increasing order of energy.

Question 114

111.According to Aufbau principle, the correct order of energy of 3d, 4s and 4p orbitals is: (A) 4p < 3d < 4s (B) 4s < 4p < 3d (C) 4s < 3d < 4p (D) 3d < 4s < 4p

Answer 114

(C) Exp: According to (n + l) Rule:- for 3d, n = 3, l for d subshell = 2 (n + l) = (3 + 2) = 5 for 4s, n = 4, l for s subshell = 0 (n + l) = (4 + 0) = 4 for 4p, n = 4, l for p subshell = 1 (4 +1) = 5 Greater the (n + l) value, greater the energy of subshell. When (n + l) value is same priority is given to less value of l. So, energy order is 4s < 3d < 4p

Question 115

112.The statement that the electron occupies available orbital singly before pairing occurs is called (A) Einstein principle (B) Rutherford hypothesis (C) Pauli’s exclusion principle (D) Hund’s rule

Answer 115

(D) Exp: According to Hund’s rule pairing of electrons in the orbitals belonging to the same subshell does not take place until each orbital belonging to that subshell has got one electron each.

Question 116

113.Nitrogen atom has unpaired electrons.This can be explained as due to: (A) Hund’s rule (B) Aufbau Principle (C) Pauli’s exclusion principle (D) Heisenberg’s uncertainty principle

Answer 116

(A) Exp: unpaired electrons in nitrogen atom can be explained by Hund’s rule N = 2, 5 1s2 2s2 2p3

Question 117

114.Number of neutrons in an atom of hydrogen is (A) One (B) Zero (C) Two (D) Three

Answer 117

(B) [SSC CHSL 2014] Exp: Hydrogen 1 1H Z = p = e = 1 A = 1 n = A - p = 0 1 - 1 = 0

Question 118

116. The subatomic particle that does not have any electric charge is a/an _____. (A) Electron (B) Proton (C) Neutron (D) All options are correct.

Answer 118

(C) (SSC CPO 2017) Exp: Neutron is a subatomic particle that does not have any electric charge. Proton has positive charge while electron has negative charge.

Question 119

117.How is atomic mass number determined? (A) By total number of protons (B) By total number of neutrons (C) By adding number of protons and neutrons (D) By total number of electrons

Answer 119

(C) (SSC CPO 2017) Exp: Atomic Mass number is equal to the sum of number of protons & neutrons. A = n + p Where A = Atomic Mass number n = no. of neutrons p = no. of protons.

Question 120

118.What are the components of nucleus of an atom? (A) Only Protons (B) Protons and Neutrons (C) Neutrons and Electrons (D) Only Neutrons

Answer 120

(B) (SSC CPO 2017) Exp: Nucleus of an atom consists of proton & neutron. While electrons revolve around the nucleus in a circular paths, called as Orbits.

Question 121

119.What is the mass of one mole of a substance in grams is called? (A) Nuclear Mass (B) Atomic Mass (C) Mass No. (D) Molecular Mass

Answer 121

(D) (SSC CPO 2017) Exp: Molecular mass is the mass of one mole of a substance in gram.

Question 122

120.Which among the following is a negatively charged ion? (A) Calcium ion (B) Zinc ion (C) Silver ion (D) Iodine ion

Answer 122

(D) (SSC CPO 2017) Exp: Iodine ion (I-) is negatively charged as it is nonmetal, it gains electron to form anion. As Ca, Zn & Ag are metals so, calcium ion (Ca2+), zinc ion (Zn2+) & silver ion (Ag+) are cations.

Question 123

121.Atomic Number is denoted by which alphabet? (A) A (B) N (C) Z (D) E

Answer 123

(C) (SSC CPO 2017) Exp: Atomic no. is the no. of protons present in nucleus of an atom. It is represented by Z.

Question 124

122. How are ‘Cations’ formed? (A) Addition of electron(B) Removal of electron (C) Addition of proton (D) Removal of proton

Answer 124

(B) (SSC CPO 2017) Exp: Cations are formed by removal of electrons. Metals generally form cations as they are electropositive elements.

Question 125

122.How are ‘anions’ formed? (A) Addition of electron(B) Removal of electron (C) Addition of proton (D) Removal of proton

Answer 125

(A) (SSC CPO 2017) Exp: Anions are formed by addition or gaining of electron. Generally non-metals form Anion as they are electronegative elements.

Question 126

123.Which amongst the following is not a Cation? (A) Aluminium ion (B) Copper ion (C) Sulphate ion (D) Zinc ion

Answer 126

(C) (SSC CGL 2017) Exp: Metals form cation as they are electron donors. So, Aluminium, copper & zinc form cation. Aluminium ion Al3+ Copper ion Cu2+ Zinc ion Zn2+ Sulphate ion 2- SO4 So, sulphate ion is anion.

Question 127

124.What are isobars? (A) Elements with same atomic number but different mass number (B) Elements with different atomic number but same mass number (C) Elements with different atomic number and different mass number (D) Elements with same atomic number and same mass number

Answer 127

(B) (SSC CGL 2017) Exp: Isobars are the elements with different atomic number but same mass number. eg:- 18 Ar40, 20Ca40 Argon & Calcium has same mass number i.e. 40 but different atomic number which are 18 and 20 respectively.

Question 128

125.Anions are formed by _____. (A) Losing of electrons (B) Gaining of electrons (C) Gaining of neutrons (D) Losing of neutrons

Answer 128

(B) (SSC CGL 2017) Exp: Anions are formed by gaining or addition of electrons. Generally, non-metals form Anions to become stable. Cl + e- Cl- valence electrons = 7 valence electrons = 8

Question 129

126.Who discovered Proton? (A) Ernest Rutherford (B) Friedrich Miescher (C) Goldstein (D) Henry Cavendish

Answer 129

(C) (SSC CGL 2017) Exp: Goldstein discovered positively charged particles called as protons.

Question 130

1.Radioactivity is the fission of - (A) Nucleus (B) Ion (C) Atom (D) Molecule

Answer 130

(A) [SSC MTS 2013] Exp: Radioactivity is the fission of unstable atomic nucleus. If n/p ratio is greater then nucleus will be unstable where n = no. of neutrons and p = no. of protons. Radioactivity is a phenomenon in which nuclei of certain elements undergo spontaneous disintegration.

Question 131

2.What is the unit of the physical quantity, Radio Activity? (A) Radian (B) Becquerel (C) Steradian (D) Kelvin

Answer 131

(B) (SSC CHSL 2016) Exp: Units of Radioactivity - (a) Becquerel (b) Curie (c) Rutherford So according to the options becquerel is unit of radioactivity.

Question 132

3.Phenomenon of Radioactivity was discovered by - (A) Becquerel (B) Rutherford (C) Curle (D) Suri

Answer 132

(A) [SSC CGL 2015] Exp: Radioactivity was discovered by Henri Becquerel (1895-96). For work in this field he, along with Marie Skodowska-Curie and Pierre Curie, received the 1903 Nobel Prize in Physics.

Question 133

4.Radioactive decay of Uranium resulted the formation of final product- (A) Radium (B) Thorium (C) Polonium (D) Lead

Answer 133

(D) [SSC CGL Exam, 2005] or Uranium eventually decays into a stable isotope of - (A) Radium (B) Thorium (C) Lead (D) Polonium (C) [SSC CPO Exam, 2011 Exp: Lead (Pb) is the final product due to the radioactive decay of Uranium. This can be explained by radioactive disintegration series. Atoms having atomic no. greater than 82 are always unstable.

Question 134

5.In India Nuclear Weapon was tested at - (A) Shri Hari Kota (B) Bangalore (C) Pokhran (D) Kanchipuram

Answer 134

(C) [SSC CPO 2007, SSC CHSL 2011] Exp: Pokhran (District Jaisalmer in Rajasthan) is a testing range of India Nuclear Programme. India tested the first underground nuclear test on 18 May 1974 in Pokhran and after this five more nuclear test occured in 11th & 13th May 1988.

Question 135

6.Radioactivity is Measured by - (A) Calorimeter (B) Polarimeter (C) Barometer (D) Geiger - Muller counter

Answer 135

(D) [SSC CGL Exam, 2006] or

Question 136

Device used for the detection and measurement of all types of radiation (alpha, beta and gamma) (A) Geiger counter (B) Polarimeter (C) Calorimeter (D) Radiometer

Answer 136

(A) (SSC CHSL 2016) Exp: Radioactivity is measured by Geiger Muller counter. It is used to count charged particles emitted by a radioactive nuclei. It is based on ionisation of gases. The ionisation chamber consists of 90% argon and 10% ethyl alcohol.

Question 137

7.Which one of the following is not a radioactive element? (A) Uranium (B) Thorium (C) Plutonium (D) Zirconium

Answer 137

(D) [SSC CPO 2005] Exp: Elements having atomic number greater than 82 are all radioactive but zirconium has atomic no. 40. So it’s not an radioactive element.

Question 138

8.The most suitable unit to express the nuclear radius is- (A) Fermi (B) Angstrom (C) Micron (D) Nanometer

Answer 138

(A) [SSC CHSL 2015] Exp: Fermi is the most suitable unit to express the nuclear radius, while atomic radius is measured in Angstrom. 1 Fermi = 10-15 m, 1 Angstrom = 10-10m

Question 139

9.The electron emitted in beta radiation originates from- (A) Inner orbits of atoms (B) Free electrons existing in nuclei (C) Decay of a neutron in a nuclei (D) Photon escaping from the nucleus.

Answer 139

(C) [SSC CHSL 2012] Exp: In -emission, a neutron of nucleus decays into a proton and a particle (electron).

Question 140

10.Which one of the following element does not show radioactivity? (A) Uranium (B) Thorium (C) Aluminium (D) Polonium

Answer 140

(C) [SSC CHSL 2014] Exp: Elements having atomic number greater than 82 are all radioactive but Aluminium has atomic no. 13 so it does not show any radioactivity.

Question 141

11.Radioactive Noble Gas is- (A) Xe (B) He (C) Ne (D) Rn

Answer 141

(D) [SSC Steno 2014] Exp: There are 6 Noble Gases He, Ne, Ar, Kr, Xe, Rn out of these only Radon is radioactive Nobel gas.

Question 142

12. There is no change in radioactive element (Mass or charge) during - (A) Gamma emission (B) Oxidation (C) Alpha emission (D) Beta emission

Answer 142

(A) [SSC MTS 2013] Exp: During Gamma emission, no change takes place in radioactive element (mass or charge) Gamma rays are emitted due to secondary effects. After the emission of an alpha particle or beta particle, the nucleus is left behind in excited state. The excess of energy is released in the form of Gamma rays. Thus Gamma rays arise from energy rearrangements in the nucleus.

Question 143

12.Which of the following is a radioactive element? (A) Cobalt (B) Uranium (C) Argon (D) Chromium

Answer 143

(B) (SSC CGL 2016) Exp: Elements having atomic no. greater than 82 are radioactive in nature. In the given options, Atomic Number of Uranium is 92 so, it is a radioactive element.

Question 144

13.Which one of the following is radioactive? (A) Cesium (B) Platinum (C) Strontium (D) Thorium

Answer 144

(D) [SSC Tax Asst. 2002] Exp: Elements having Atomic no greater than 82 are radioactive in Nature. Atomic number of thorium is 90, so it is radioactive.

Question 145

14.Which one of the following is not a radio-active element? (A) Uranium (B) Thorium (C) Radium (D) Cadmium [SSC Selection Officer (Audit) 2008]

Answer 145

(D) Exp: Elements having Atomic no greater than 82 are radioactive in Nature. Atomic no. of Cadmium is 48, so it is not radioactive.

Question 146

15.Radioactive samples are stored in lead boxes. Lead is used because it is: (A) Heavy (B) Strong (C) Good absorber (D) Bad conductor

Answer 146

(C) (SSC CHSL 2009) Exp: Lead is good absorber of radioactive radiations so radioactive samples are stored in lead boxes.

Question 147

16.The nuclear forces are - (A) Charge independent (B) Spin independent (C) Charge symmetric (D) Long range.

Answer 147

(A) [SSC MTS 2011] Exp: It is seen from experiment that the attractive force between two neutrons (n-n) is nearly equal to that between two protons (p-p) or between a proton and a neutron (p-n). Thus the nuclear force does not depend on the charge of the particle.

Question 148

17.The lightest radioactive element is (A) Deuterium (B) Polonium (C) Tritium (D) Uranium

Answer 148

(C) (SSC CHSL 2016) Exp: The lightest radioactive element is tritium. It is radioactive isotope of hydrogen.

Question 149

18.An element that does not occur in nature but can be produced artificially is (A) Thorium (B) Radium (C) Plutonium (D) Uranium

Answer 149

(C) (SSC CHSL 2016) Exp: Plutonium element does not occur in nature but can be produced artificially.

Question 150

19.Which of the following is a radioactive element? (A) Cobalt (B) Uranium (C) Argon (D) Chromium

Answer 150

(B) (SSC CHSL 2016) Exp: Elements having atomic no. greater than 82 are radioactive in nature. Atomic number of Uranium is 92, so it is radioactive element.

Question 151

20.Radioactive elements emit(A) Radiowaves (B) Infrared waves (C) Ultraviolet waves (D) , and radiations

Answer 151

(D) (SSC CHSL 2016) Exp: Radioactive elements emit a, b and g radiations. Emission of g radiation takes place after emission of a and b radiations.

Question 152

21.Which of the following caused radioactive pollution along the coast of Kerala? (A) Plutonium (B) Zinc (C) Thorium (D) Radium

Answer 152

(C) (SSC CHSL 2016) Exp: Monazite sand is an ore of thorium it is found near coastal area of Kerala. So thorium is responsible for radioactive pollution near Kerala coast.

Question 153

22.Which of the following elements is not radioactive? (A) Radium (B) Plutonium (C) Zirconium (D) Uranium

Answer 153

(C) (SSC CAPF’s SI & CISF ASI 2013) Exp: Zirconium (Z = 40) is not radioactive element

Question 154

.24. Which of the following elements does not exhibit natural radioactivity? (A) Uranium (B) Thorium (C) Aluminium (D) Polonium

Answer 154

(C) [SSC LDC 2014] Exp: Aluminium having atomic number 13, does not exhibit natural radioactivity.

Question 155

25.The unstability of a nucleus is due to: (A) Higher electron-to-proton ratio (B) High neutron-to-proton ratio (C) Low electron-to-proton ratio (D) Low neutron-to-electron ratio.

Answer 155

(B) Exp: When n/p ratio of nuclei is high, the nuclei donot lie in the stability belt and hence becomes unstable. Being unstable such nuclei undergo spontaneous radioactive disintegration.

Question 156

26.Which of the following nuclei is unstable? (A) 5B10 (B) 4Be10 (C) 7N14 (D) 8O16

Answer 156

(B) Exp: The nuclei having the same number of neutrons and protons are stable while the nuclei having different number of neutrons and protons are unstable. The number of neutrons (n) and protons (p) in the given nuclei are is : (A) 5B10 p = 5, n = 10 - 5 = 5, (B) 4Be10 p = 4, n = 10 - 4 = 6, (C) 7N14 p = 7, n = 14 - 7 = 7 (D) 8O16 p = 8, n = 16 - 8 = 8.

Question 157

27. A radioisotope will emit: (A) -and -particles simultaneously. (B) -and -rays simultaneously. (C) -and -rays simultaneously (D) -or -rays and then -rays.

Answer 157

(D) Exp: A radioisotope first emits or particle and becomes unstable. Then it emits -rays

Question 158

27.Unstab le substances exh ib it higher radioactivity due to: (A) Low p/n ratio (B) High p/n ratio (C) p/n = 1 (D) None of these

Answer 158

(A) Exp: The nuclei having high n/p ratio or low p/n ratio are unstable so they are highly radioactive.

Question 159

28.Which among the following is false about alpha particles? (A) They have high ionizing power (B) They have high penetrating power (C) They have high kinetic energy (D) They are positively charged helium nuclei

Answer 159

(B) (SSC CHSL 2016) Exp: Alpha particles have small penetrating power due to relatively larger size. They are stopped by a piece of aluminium foil of 0.1 nm thickness.

Question 160

29.Which type of reaction produces the most harmful radiation? (A) Fusion (B) Fission (C) Chemical reaction (D) Photo Chemical

Answer 160

(B) [SSC CGL 2011] Exp: Nuclear Fission type nuclear reactions produce the most harmful radiations. Products of Nuclear fission are usually unstable and radioactive in nature while products of fusion are usually stable and non-radioactive in nature.

Question 161

30.The element which is commonly used in nuclear reactor for producing electricity in nuclear fission is (A) Radium (B) Plutonium (C) Uranium (D) Deuterium

Answer 161

(C) [SSC S. Officer (Audit) 2001] Exp: Uranium - 235 is commonly used in nuclear reactors for producing electricity in nuclear fission. Uranium is a fissile material.

Question 162

31.High amount of energy is released in the explosion of atomic bomb is due to- (A) Conversion of Mass into energy (B) Conversion of Chemical Energy into thermal energy. (C) Conversion of Mechanical energy into nuclear energy (D) Conversion of neutrons into Protons

Answer 162

(A) [SSC MTS 2013] Exp: The release of energy takes place because in this reaction some mass is lost, since mass of the reactants is more than the mass of the products. The mass lost is converted into energy which is released in the reaction. The energy released is calculated with the help of Einstein’s mass energy relationship:- E = mc² 235U92 + 0n1 56Ba141 + 36Kr92 + 30n1 + E

Question 163

32.Nuclear Power Reactor acts on the Principle of- (A) Fission (B) Fusion (C) Thermal Heating (D) Combined Effect of all three given above

Answer 163

(A) [SSC Tax Asst. 2008] Exp: Nuclear power reactor acts on the principle of nuclear fission. In nuclear reactor energy is produced by the controlled chain reaction 235U92 + 0n1 56Ba141 + 36kr92 + 30n1

Question 164

33.Name the particle that is most essential to continue the chain reaction during the fission of Uranium- (A) Electron (B) Proton (C) Neutron (D) Positron

Answer 164

(C) [SSC Matric Level 2002, 2011] Exp: Neutron particle is the most essential to continue the chain reaction during the fission of Uranium. After disintegration, three neutrons are produced among these two are absorbed while remaining third neutron initiates chain reaction.

Question 165

34.Who Invented the nuclear reactor? (A) Enrico Fermi (B) Adolf Gaston Eugen Fick (C) Sandford Fleming (D) Benoit Fourneyron

Answer 165

(A) (SSC CHSL 2016) Exp: Enrico Fermi was an Italian physicist who invented nuclear reactor. Nuclear reactor is also known as an Atomic Pile or Atomic Reactor.

Question 166

35.The two elements which are used to absorb the neutrons in nuclear fission during chain reaction - (A) Boron and Cadmium (B) Boron and Plutonium (C) Cadmium and Uranium (D) Uranium and Boron

Answer 166

(A) [SSC CGL 2011, SSC CPO 2010] or Control rods used in the nuclear reactor are made of: (A) Fe (B) Graphite (C) Cd (D) Be (C) Exp: The function of control rods used in the nuclear reactor is to control the number of neutrons. This is achieved by using the rods of cadmium or boron as control rods which absorb the neutrons and thus control their number.

Question 167

36.Graphite is used as a………… in nuclear reactors. (A) Fuel (B) Lubricant (C) Moderator (D) Electric Insulator

Answer 167

(C) [SSC CGL 2008] Exp: Moderator slowdown the speed of fast moving neutrons. The most commonly used moderators are Ordinary water and Graphite. The most efficient moderator is Helium. The next most efficient one is heavy water (D2O) but this is so expensive. So it is used only in research reactors.

Question 168

37.Which one of the following used as a moderator in nuclear reactor? (A) Uranium (B) Radium (C) Thorium (D) Graphite

Answer 168

(D) [SSC CHSL 2012] Exp: Moderator slowdown the speed of fast moving neutrons. The most commonly used moderators are Ordinary water and Graphite. The most efficient moderator is Helium. The next most efficient one is heavy water (D2O) but this is so expensive. So it is used only in research reactors.

Question 169

38.Heavy water used as a coolant in nuclear reactor. Heavy Water is: (A) Water rich in Minerals (B) Ozonised water (C) Water containing Minerals of Heavy metals (D) Water containing heavy Isotopes of Hydrogen atom

Answer 169

(D) [SSC CHSL Exam, 2014] Exp: Heavy water (D2O) contains heavy isotope of hydrogen atom (Deuterium). Liquid alloy of sodium and potassium is also used as coolant: It takes away the heat to the exchanger.

Question 170

39.In nuclear reactor, Neutrons are slowdown by the- (A) Fissionable Product (B) Moderator (C) Controlling rod (D) Coolant system

Answer 170

(B) [SSC CGL 2013] Exp: In nuclear reactor neutrons are slowdown by the moderator. The most commonly used moderators are Ordinary water and Graphite.

Question 171

40.Alpha particles are ___________. (A) Twice the mass of beta particles (B) Negatively charged (C) Just like helium nuclei (D) Lower in ionizing power as compared to gamma rays

Answer 171

(C) (SSC CHSL 2016) Exp: Alpha particles are formed after the removal of 2 electrons from helium atom. So alpha particles are just like helium nuclei.

Question 172

41.The radiation that can penetrate deepest in our body (A) UV-radiation (B) Alpha-particles (C) -particles (D) Gamma-particles

Answer 172

(D) [SSC CGL 20015] Exp: Due to high velocity and non material character gamma rays are more penetrating than alpha, beta and X-rays.

Question 173

42.The isotope of Uranium used in atomic reactors is (A) U235 (B) U236 (C) U237 (D) U232

Answer 173

(A) [SSC Section officer (Audit) 2008] Exp: Uranium 235 is used as fuel in atomic reactor.

Question 174

43.Which of the following can be used to absorb neutrons to control the chain rection during nuclear fission? (A) Boron (B) Heavy water (C) Uranium (D) Plutonium

Answer 174

(A) [SSC CGL 2011] Exp: Boron or Cadmium rod is used to absorb neutrons to control the chain reaction during nuclear fission. When these rods completely push into reactor this position is known as shutdown of nuclear reactor.

Question 175

44.Which of the following is used as a moderator in nuclear reactors? (A) Thorium (B) GraphiteCesium (D) Radium

Answer 175

(B) (SSC CHSL 2016) Exp: Graphite is used as a neutron moderator in nuclear reactor. Heavy water is the best neutron moderator.

Question 176

45.Which of the following Radiations, is not emitted during radioactivity? (A) rays (B) rays (C) rays (D) Cathode rays

Answer 176

(D) (SSC CHSL 2016) Exp: Cathode rays are not emitted during radioactivity. A radioisotope first emits or particle and becomes unstable. Then it emits -rays

Question 177

46.Which of the following has the minimum penetrating power? (A) - ray (B) - ray (C) - ray (D) - ray

Answer 177

(A) [SSC CAPFs SI, CISF ASI & Delhi 2005] Exp: a - particles, being more massive have minimum penetrating power.

Question 178

47.U-235 belongs to which member of series? (A) Thorium series (B) Actinium series (C) Uranium series (D) Neptunium series

Answer 178

(B) [SSC CPO 2016] Exp: Uranium (U-235) belongs to actinium series. Actinium is also known as (4n + 3) series. 4n for Thorium series 4n + 1 for Neptunium series 4n + 2 for Uranium series 4n + 3 for Actinium series

Question 179

48.Loss of a - particle is equivalent to (A) Increase of one proton only (B) Decrease of one neutron only (C) Both (A) and (B) (D) None of these

Answer 179

(C) Exp: If an isotope bXa loses a particle, it is converted into b+1Ya. bXa b+1Y -or -1e a 0 No. of protons in X = b No. of protons in Y = b + 1 No. of neutron in X = (a - b) No. of neutrons in Y = a - (b + 1) = a - b - 1 Obviously Y has one more proton (increase of proton) and one less neutron (decrease of one neutron) than X.

Question 180

49.Isobar of a nuclide is formed by: (A) one -emission (B) one -emission (C) emission (D) emission.

Answer 180

(B) Exp: Isobars are nuclides which have same mass numbers(A) but different atomic numbers (Z). During - deacy, no changes in mass number takes place. bXa -1e0 (-particle) + b+1Ya

Question 181

50.An element X loses and two particles in three successive stages. The resulting element will be: (A) an Isobar of X (B) an Isotope of X (C) X itself (D) an Isotone of X

Answer 181

(B) Exp: When X loses and one (2He4) and two (-1e0) particles, the mass number of the daughter element is 4 units less than that of X and the atomic number is the same as that of X. bXa 2He4 + 2 -1e0 + bXa-4 Thus the daughter elements is the isotope of X.

Question 182

51.Which of the following element belongs to 4n series? (A) Pb-206 (B) Pb-207 (C) Pb-208 (D) Bi-209

Answer 182

(C) Exp: 4n series is that in which the mass number of all the members of the series are exactly divisible by 4. Since it is only 208 which is completely divisible by 4, Pb-208 belongs to 4n series.

Question 183

52.Nuclear reactors are based on: (A) Nuclear fission (B) Natural radioactivity (C) Nuclear fusion (D) Spontaneous chemical reaction

Answer 183

(A) Exp: In the nuclear reactor energy is produced by the fission of U235.

Question 184

53.Which of the following is a thermonuclear reaction? (A) 92U238 + 0n1 93Np239 + -1e0 (B) 41H1 2He4 + 2 +1e0 (C) 92U238 + 6C12 98Cf246 + 40n1 (D) 13Al27 + 2He4 15P30 + 0n1

Answer 184

(B) Exp: Since in nuclear reactions (B), lighter nuclei of 1H1 fuse together to form heavier helium nucleus (2He4), it is a nuclear fusion reaction. Since nuclear reactions can take place only at extremely high temperatures only (> 106 K), these reactions are known as thermo-nuclear reactions.

Question 185

54.In a nuclear reactor heavy water is to: (A) Transfer the heat from the reactor (B) Provide high speed neutrons for fission reaction (C) Reduce the speed of fast moving neutrons (D) Increase the speed of neutrons.

Answer 185

(C) Exp: Heavy water is used as moderator. The function of a moderator is to reduce the speed of fast moving neutrons and transfers the heat from the reactor.

Question 186

55.Which one of the following takes place during a nuclear fusion? (A) A heavy nucleus bombarded by neutrons breaks up (B) A heavy nucleus breaks up spontaneously (C) Two light nuclei combine to form a heavy nucleus (D) A light nucleus breaks up spontaneously

Answer 186

(C) (SSC CGL 2016) Exp: Nuclear fusion: A nuclear reaction in which two lighter nuclei are fused together to form a heavier nuclei is called as Nuclear Fusion. Fusion reactions are also called as thermonuclear reactions. Note: Hydrogen bomb and energy of stars (Sun) are due to on Nuclear Fusion.

Question 187

56.The energy of the Sun is mainly due to (A) Nuclear fission (B) Radioactivity (C) Heat (D) Nuclear fusion

Answer 187

(D) [SSC Matric Level 2002] Exp: The energy of the Sun and stars is due to fusion reaction.

Question 188

57.The source of enormous energy of Sun is: (A) Fission of uranium (B) Fusion of hydrogen nuclei to form helium nucleus. (C) Fusion of deuterium and tritium (D) Fission of tritium to form helium.

Answer 188

(B) Exp: In the Sun, four hydrogen atoms (protons) get fused to give one 2He4 nucleus with the emission of two positrons (+1e0). A large amount of energy is also produced. 41H1 Fusion 2He4 + 0 1 2 e + 24.64 MeV

Question 189

58.The radiant energy of Sun is due to: (A) Disintegration (B) Nuclear fission (C) Nuclear fusion (D) Combustion.

Answer 189

(C) Exp: The radiant energy of the sun is due to the fusion of four 1H1 nuclei to form one 2He4 nucleus with the emission of two positrons (+1e0). In this reaction, a large amount of energy is also produced. 4 1H1 Fusion 2 2He4 + 0 1 2 e + 24.64 MeV

Question 190

59.Nuclear fusion is the source of energy in:(A) Atomic bomb (B) Hydrogen bomb (C) The Sun (D) The Moon.

Answer 190

(C) Exp: In the Sun, four hydrogen atoms (protons) get fused to give one 2He4 nucleus with the emission of two positrons (+1e0). A large amount of energy is also produced. 41H1 Fusion 2He4 + 0 1 2 e + 24.64 MeV

Question 191

61. The First Time atomic bomb was released at- (A) Nagasaki (B) Hiroshima (C) Tokyo (D) Hongkong

Answer 191

(B) [SSC MTS 2011] Exp: First time atomic bomb was released by America at Hiroshima Japan on 6 August named Little boy (235U) and on 9th August 1945 at Nagasaki named Fatman (239Pu)

Question 192

63.Hydrogen Bomb is based upon the Principle of- (A) Controlled Nuclear Fission (B) Uncontrolled Nuclear Fission (C) Controlled Nuclear Fusion (D) Uncontrolled Nuclear Fusion

Answer 192

(D) [SSC CGL 2011] Exp: Energy produced in hydrogen bomb is due to the nuclear fusion reactions between duterium (1H2) and tritium (1H3) nuclei. This fusion gives helium nucleus (2He4) and one neutron (0n1). In this reactions, an uncontrolled amount of energy is also generated. 1H2 + 1H3 Fusion 2He4 + 0n1 + 17.6 Me V

Question 193

64.How many countries explode the atom bomb before India? (A) 5 (B) 4 (C) 6 (D) 3

Answer 193

(A) [SSC CGL 2005] Exp: USA (1945), USSR (1949), UK (1952), France (1960), China (1964) exploded atom bomb before India (1974).

Question 194

65.Who developed Hydrogen Bomb? (A) Wernher Von Braun (B) J. Robert Oppen Heimer (C) Edward Teller (D) Samuel Cohen

Answer 194

(C) [SSC 2016] Exp: Hydrogen Bomb was discovered by Edward Teller. Hydrogen bomb is based on nuclear fusion. It is 1000 times more powerful than atom bomb.

Question 195

66.Who developed atom bomb? (A) Warner Wan Bron (B) J. Robert Openheimer (C) Edward Taylor (D) Samuel Koehen

Answer 195

(B) [SSC CGL 2002] Exp: Atom bomb was developed by J. Robert Openheimer. Manhattan Project was responsible for the creation of the first functioning atomic bomb.

Question 196

67.Atomic explosion is triggered by (A) Thermo nuclear reaction (B) Chemical reaction (C) Controlled chain reaction (D) Uncontrolled chain reaction

Answer 196

(D) [SSC CGL 2011] Exp: Atomic explosion is triggered by uncontrolled chain reaction (nuclear fission).

Question 197

68.What were the names of Atom Bombs dropped on Japan? (A) Little Boy & Fat Man (B) Little Man & Fat Boy (C) Little Girl & Fat Woman (D) Little Woman & Fat Girl

Answer 197

(A)Exp: Little boy & Fatman atom bombs were dropped on Japan by America during second world war.

Question 198

69.Nuclear bombs were dropped on Hiroshima and Nagasaki during the________. (A) World War I (B) Asian War I (C) Gulf War II (D) World War II

Answer 198

(D) (SSC CHSL 2016)

Question 199

69. The fissile material commonly used in atomic bomb is (are): (A) 92U235 (B) 92U238 (C) 94Pu239 (D) 90Th232

Answer 199

(A) Exp: The atomic bomb contains two pieces of U235 each of sub-critical mass. One piece is called wedge and the other is called target. The size of the fissile material, U235 should not be less than the critical mass.

Question 200

70.Atom bomb is based on: (A) Nuclear fusion (B) Nuclear fission (C) Induced radioactivity (D) Disintegration

Answer 200

(B) Exp: The large amount of energy is produced by the fission of large piece of 92U235 by the neutrons in Atom Bomb.

Question 201

71.The radio-active element used in heart pacemakers is (A) Uranium (B) Deuterium (C) Plutonium (D) Radium

Answer 201

(C) [SSC Section Officer (Audit) 2001] Exp: Plutonium is formed in nuclear power reactors from uranium. Early heart pacemakers used Pu-238 as the power source.

Question 202

72.Which of the following Isotope is used in the production of Nuclear Energy? (A) U-239 (B) U-235 (C) U-238 (D) U-236

Answer 202

(B) [SSC CGL 2010] Exp: U-235 is used in the production of Nuclear energy. In Nuclear reactor, energy is produced by the controlled chain reaction.

Question 203

73.Tritium is an Isotope of - (A) Oxygen (B) Hydrogen (C) Phosphorous (D) Nitrogen

Answer 203

(B) [SSC CHSL Exam, 2013] Exp: Tritium (1H3) is an isotope of hydrogen. It is the lightest radioactive element.

Question 204

74.Find the odd one out of following? (A) Trombay (B) Tarapur (C) Kalpakkam (D) Narora

Answer 204

(A) [SSC Steno Exam, 2014] Exp: Trombay is odd one out of given options because there is no nuclear reactor but rest of places has Nuclear reactor. Note:- Rawatbhata,Kakarapar, Kaiga & Kudan-Kulum also have nuclear reactors.

Question 205

75.In the treatment of skin disease the radioactive isotope used is- (A) Lead (B) Cobalt (C) Phosphorous (D) Iodine

Answer 205

(C) [SSC Steno 2012] Exp: Radioactive Phosphorous - 32 is used in the treatment of skin disease.

Question 206

76.Curie point is the temperature at which- (A) Matter becomes radioactive (B) Metal looses Magnetic Properties (C) Metal looses conductivity (D) Transmutation of Metal occours

Answer 206

(B) [SSC CGL 2010] Exp: On heating metal at temperature greater than Curie temperature metal looses it magnetic properties - Metal - Curie temperature (ºC) Fe (Iron) - 770 Co(Cobalt) - 1130 Ni (Nickel) - 358

Question 207

77.What is the name of the system, which uses radioactivity to decide the period of materials of-pre-historic period? (A) Radium dating (B) Uranium dating (C) Carbon dating (D) Deuterium dating

Answer 207

(C) [SSC Section Officer 2001] Exp: Radio carbon dating - By using the half life period of 14C, it is possible to determine the age of various objects. In living material the ratio of 14C to 12C remains constant. When the tissue in an animal or plant dies. 14C decreases because the intake and utilization of 14C do not occur. Therefore in the old tissue the ratio of 14C to 12C would decrease, depending on the age of this tissue.

Question 208

78.The proper rays for radio carbon dating are: (A) UV rays (B) IR rays (C) Cosmic rays (D) X-rays.

Answer 208

(C) Exp: Cosmic rays have neutrons (present in the upper atmosphare) convert 7N14 to radioactive 6C14. 7N14 + 0n1 (present in the cosmic rays) 6C14 (radioactive carbon) + 1H1

Question 209

79.For which purpose is Radiocarbon dating technique is used? (A) To estimate soil contamination (B) To estimate the amount of water in fossils (C) To estimate the age of fossils (D) To estimate the quality of soil

Answer 209

(C) (SSC CHSL 2016) Exp: Radio carbon dating - By using the half life period of 14C, it is possible to determine the age of various objects. In living material the ratio of 14C to 12C remains constant. When the tissue in an animal or plant dies. 14C decreases because the intake and utilization of 14C do not occur. Therefore in the old tissue the ratio of 14C to 12C would decrease, depending on the age of this tissue.

Question 210

80.Which of the following reaction is the main cause of energy radiated from Sun? (A) Nuclear fission (B) Nuclear fusion (C) Chemical reaction (D) Diffusion reaction

Answer 210

(B) (SSC CPO 2017) Exp: The main cause of energy radiated from Sun is Nuclear fusion. In the Sun, four hydrogen atoms (protons) get fused to give one 2He4 nucleus with the emission of two positrons (+1eo). A large amount of energy is produced. 41H1 fusion 2He4 + 2+1eo + 24.64 MeV.

Question 211

81.Which of the following is used as control rods in Atomic reactor? (A) Sodium (B) Uranium (C) Graphite (D) Boron

Answer 211

(D) (SSC CPO 2017) Exp: Boron or Cadmium rod is used to absorb neutrons to control the chain reaction during nuclear fission.

Question 212

82.Which of the following is used as coolant in Atomic reactor? (A) Water (B) Uranium (C) Graphite (D) Boron

Answer 212

(A) (SSC CPO 2017) Exp: Coolant is a device in nuclear reactor which is used to remove heat generated from it & transfers to electrical generators (for electricity generation) & environment. Water is used as an coolant in Nuclear Reactor.

Question 213

83.Which of the following is used as moderator in atomic reactor? (A) Sodium (B) Uranium (C) Graphite (D) Boron

Answer 213

(C) (SSC CPO 2017) Exp: Moderators slow down the speed of fast moving neutrons. The most commonly used moderators are Graphite & Ordinary water.

Question 214

84.Which of the following is a characteristic of an exothermic reaction? (A) Release of heat (B) Absorption of heat (C) Doesn’t involve any change in temperature (D) None of the option is correct

Answer 214

(A) (SSC CGL 2017) Exp: Exothermic reactions are those in which heat is released. The energy of reactants is more than the energy of products. eg:- Nuclear reactions are exothermic reactions.

Question 215

85.What is an endothermic reaction? (A) Reaction in which heat is released. (B) Reaction in which heat is absorbed. (C) Reaction in which neither heat is released nor absorbed. (D) None of these.

Answer 215

(B) (SSC CGL 2017) Exp: The reactions in which heat is absorbed are called as endothermic reactions. eg:- CaCO3 CaO + CO2 For decomposition of CaCO3, energy is given in the form of heat & energy is absorbed.

Question 216

1.What happens in an Oxidation reaction? (A) Protons are lost (B) Electrons are lost (C) Neutrons are lost (D) Electrons are gained

Answer 216

(B) (SSC CHSL 2016) Exp: Removal of electrons occur in Oxidation process. eg:- Mg (s) Mg2++2e-

Question 217

2.Wh ich among the fo llowing is not a characteristic of Oxidation reaction? (A) It involves addition of hydrogen (B) It involves addition of oxygen (C) It involves loss of electrons (D) It involves addition of electronegative element

Answer 217

(A) (SSC CHSL 2016) Exp: Addition of H2 is a Reduction process. While Oxidation is defined as:- (a) Addition of Oxygen or electronegative element:- eg:- 2Mg(s) + O2(g) 2MgO(s) (0) (+2) Oxidation Number (b) Removal of Hydrogen:- eg:- H2S + Cl2 2HCl + S (-2) (0) Oxidation Number (c) Loss of Electrons :- eg:- Fe(s) Fe2+ + 2e- (0) (+2) Oxidation Number

Question 218

3.The liberation of oxygen during photosynthesis is due to__________. (A) Hydrolysis of carbohydrates (B) Photolysis of water (C) Reduction of CO2 (D) Breakdown of chlorophyll

Answer 218

(B) (SSC CGL 2016) Exp: The liberation of oxygen during photosynthesis is due to photolysis of water. Photolysis of water is the process of breakdown of water molecule into protons & Oxygen under the influence of light during photosynthesis reaction. 6CO +6H O 2 2 C H O +6O 6 12 6 2 Reduction chlorophyll, hv Oxidation - 2 4 4 H O H e O 2 2 In this reaction O2 is obtained from water.

Question 219

4.When Hydrogen combusts in air, then formed- (A) Ammonia (B) Water (C) Methane (D) Carbonic acid.

Answer 219

(B) [SSC Matric Level 1999, SSC Steno 2010] Exp: When Hydrogen burns in air, then it forms water and energy is released. This is used in Hydrogen fuel. 2H2(g) + O2(g) 2H2O(g) + Energy.

Question 220

5.Browning of paper in old books is caused by (A) Frequent use (B) Lack of aeration (C) Collection of dust (D) Oxidation of cellulose

Answer 220

(D) [SSC MTS Exam, - 1999] Exp: Browning of paper in old books is caused by oxidation of cellulose. This phenomenon is called as foxing (stains of Reddish brown colour).

Question 221

6.Oxygen has (+) oxidation number only in (A) OF2 (B) Cl2O (C) H2 O (D) N2O

Answer 221

(A) [SSC Steno. 2011] Exp: Oxygen has (+)ve oxidation no. only in OF2. Let the oxidation no. of O be x. then x + 2 (-1) = 0 x = +2

Question 222

7.The oxidation number of nickel in K4[Ni(CN)4] is (A) 0 (B) +4 (C) -4 (D) +8 [SSC MTS 2013]

Answer 222

(A) Exp: The oxidation no. of Ni in K4[Ni(CN)4] is 0 Let the oxidation no. of Ni be x. then 4(+1) + x + 4 (- 1) = 0 x = 0

Question 223

8.The oxidation number of sulphur in S8, S2F2 and H2S respectively are (A) 0, +1 and -2 (B) + 2, +1 and -2 (C) 0, +1 and +2 (D) -2, +1 and -2

Answer 223

(A) Exp: The oxidation no. of sulphur in S8, S2F2 and H2S respectively are 0, +1 and -2. In homoatomic molecule (S8) oxidation no. of an element is zero. S2F2 Let the oxidation no. of S be x 2x + 2 (-1) = 0 x 1 H2S Let the oxidation no. of S be x 2 (+1) + x = 0 x -

Question 224

9.Nitrogen forms a variety of compounds in all oxidation states ranging from- (A) - 3 to +5 (B) -3 to +3 (C) -3 to +4 (D) -3 to +6

Answer 224

(A) [SSC Const. (GD) 1999] Exp: Nitrogen shows oxidation states from -3 to +5 in various compounds. for eg: In NH3 oxidation state of Nitrogen is -3 while in HNO3 oxidation of Nitogen is +5.

Question 225

10.Oxidation state of Fe in Fe3O4 is - (A) 3 2 (B) 4 5 (C) 5 4 (D) 8 3

Answer 225

(D) Exp: Fe3O4 Let the oxidation number of Fe be x 3x + 4 (-2) = 0 8 x 3

Question 226

11.The oxidation state of Cr in K2Cr2O7 is - (A) +7 (B) +6 (C) +3 (D) +2

Answer 226

(B) Exp: K2Cr2O7 Let the oxidation number of Cr be x 2 (+1) + 2x + 7 (-2) = 0 x = +6

Question 227

12.In H2O2, oxidation state of oxygen is (A) -2 (B) -1 (C) .0 (D) -4

Answer 227

(B) (SSC CHSL 2016) Exp: In H2O2, oxidation state of oxygen is -1. Let the oxidation number of O be x 2 (+1) + 2x = 0 X = -1

Question 228

13.In which of the following compounds transition metal has zero oxidation state? (A) CrO5 (B) Fe3O4 (C) FeSO4 (D) Fe(CO)5

Answer 228

(D) (SSC CHSL 2016) Exp: Oxidation of CO is zero. So oxidation no. of Fe in Fe(CO)5 is zero.

Question 229

14.Cooking oil is converted into vegetable ghee by the process of- (A) Hydrogenation (B) Oxidation (C) Condensation (D) Crystallization

Answer 229

(A) [SSC CPO 2011] Exp: Vegetable oils are converted into vegetable ghee when vegetable oils are reacted with Hydrogen gas in the presence of catalyst Ni/Pd. This process is known as Hydrogenation or Reduction of vegetable oil. During this process trans fat is formed. Vegetable oil + H2 Ni Pd / Vegetable ghee or

Question 230

In the Industrial production of vegetable ghee, the process involved is - (A) Dissociation (B) Reduction (C) Oxidation (D) Ionization

Answer 230

(B) Exp: Vegetable oils are converted into vegetable ghee when vegetable oils are reacted with Hydrogen gas in the presence of catalyst Ni/Pd. This process is known as Hydrogenation or Reduction of vegetable oil. During this process trans fat is formed. Vegetable oil + H2 Ni Pd / Vegetable ghee Reduction is defined as:- 1. Removal of Oxygen or electro-negative element Δ 2MgO 2Mg + O2 (+2) (0) Oxidation Number 2. Addition of Hydrogen:- F2 + H2 2HF (0) (-1) Oxidation Number 3. Gain of electrons. Mg2+(s) + 2e- Mg(s) (+2) (0) Oxidation Number

Question 231

15.Which of the following causes Rusting of iron? 1. Oxidation 2. Reduction 3. Chemical reaction with oxygen 4. Chemical reaction with CO2 (A) 1 and 2 (B) 2 and 3 (C) 3 and 4 (D) 1 and 3

Answer 231

(D) [SSC CHSL 2011] Exp: In the presence of Moisture and oxygen, oxidation occurs due to which a Reddish-Brown Layer is deposited on iron. This Reddish brown Layer on iron is called Rust. Its chemical formula is Fe2O3.xH2O. Deposition of rust on metals is called Rusting.

Question 232

16.Rusting of Iron is - (A) Due to oxidation (B) Due to carbonation (C) Due to epoxidation (D) Due to corrosion

Answer 232

(A) [SSC Tax Asst. 2007] Exp: Rusting of iron is due to oxidation of iron. In oxidation loss of electrons or increase in oxidation no. takes place in atom. 4Fe + 3O2 Watervapour Fe2O3. x H2O

Question 233

17.The rusting of iron metal in air needs both- (A) Carbon dioxide and Moisture (B) Water and Paint (C) Oxygen and grease (D) Oxygen and Moisture

Answer 233

(D) [SSC CGL 2014] Exp: Both O2 & Water are needed for rusting to occur.Which of the following is required for the rusting of iron? (A) Oxygen and carbon dioxide (B) Oxygen and water (C) Only carbon dioxide (D) Only oxygen (B) [SSC CPO 2011] Exp: Rust is hydrated iron oxide (Fe2O3.xH2O). The presence of water and oxygen is essential for the rusting of iron. Impurities in the iron, the presence of water vapour, acids, salts and carbon dioxide hastens rusting. Pure iron does not rust in dry and carbon dioxide free air.

Question 234

18.What is Rusting of Iron? (A) Physical change (B) Electric change (C) Photo Chemical change (D) None of the above

Answer 234

(D) [SSC MTS 2013] Exp: Rusting of iron is a chemical change. Chemical changes are the changes in which new product is formed and properties of this new product is completely different from the base substances. The product formed by the chemical change cannot be reversed in its base matter Example Rusting of Iron, curding of Milk, cooking of food, burning of candle etc.

Question 235

19.Iron rusts quickly in - (A) Rain water (B) Distilled water (C) Sea water (D) River water

Answer 235

(C) [SSC CGL 2014] Exp: Iron reacts with oxygen in the presence of water and air and forms rust. Water containing salt (such as sea water) cause rusting of iron faster.

Question 236

20.The rusting of iron- (A) Decreases its weight(B) Increases its weight (C) Remains same (D) Can’t say (unpredictable)

Answer 236

(B) [SSC MTS 2008] Exp: Rusting of iron is a chemical process. By rusting weight of iron increases due to deposition of hydrated iron oxide layer.

Question 237

21.The coating of thin layer of zinc on steel or iron object is known as (A) Hot dipping (B) Tinning (C) Galvanising (D) Electroplating

Answer 237

(C) [SSC MTS 1999] Exp: The coating of thin layer of zinc on steel or iron object is known as galvansing. Galvanising process is used to protect iron from rust.

Question 238

22.The metal, used to galvanise iron to protect it from rusting is (A) Zinc (B) Chromium (C) Lead (D) Antimony

Answer 238

(A) [SSC MTS 2002] Exp: Zinc metal is used to galvanise iron to protect it from rusting.

Question 239

23.Which metal does not undergo corrosion due to the formation of Oxide layer? (A) Copper (B) Iron (C) Aluminium (D) Zinc

Answer 239

(C) [SSC MTS Exam, - 2002] Exp: Aluminium metal does not rust or corrode in moist conditions. Its surface is protected by layer of aluminium oxide (Al2O3). This prevents metal comes into contact with air and oxygen.

Question 240

24.The metal chiefly used for galvanising iron is: (A) Zinc (B) Mercury (C) Cadmium (D) Tin

Answer 240

(A) [SSC MTS Exam, - 2006] Exp: Zinc metal is chiefly used for galvanising iron because zinc is more reactive than iron.

Question 241

25.The process of deposition of a layer of Zinc over water pipes for being protected from rusting is known as- (A) Depositing a Layer of Zinc (B) Formation of alloy (C) Vulcanization (D) Galvanization

Answer 241

(D) [SSC CGL, MTS 2011, 1991, 2002, 2001] Exp: The process of deposition of a layer of Zinc over iron metal is called Galvanization. Iron having layer of zinc over it known as Galvanized iron and thus iron is prevented from rusting.

Question 242

26.Which metal is used to Galvanize iron? (A) Copper (B) Zinc (C) Tin (D) Nickel

Answer 242

(B) [SSC CGL Exam, 2014] Exp: Galvanization (galvanizing) is the process of applying a protective zinc coating to steel or iron, to prevent rusting. The most common method is hot-dip galvanizing, in which metal is submerged in a bath of molten zinc.

Question 243

27.To protect the iron from getting rusted, the coat of zinc is applied on it. This process is known as- (A) Galvanization (B) Reduction (C) Corrosion (D) Calcination

Answer 243

(A) [SSC CGL Exam, 2014] Exp: Galvanization (galvanizing) is the process of applying a protective zinc coating to steel or iron, to prevent rusting. The most common method is hot-dip galvanizing, in which metal is submerged in a bath of molten zinc.

Question 244

28.Which of the following is not favourable to prevent iron from rusting? (A) Annealing (B) Applying grease (C) Galvanization (D) Painting

Answer 244

(A) [SSC CGL Exam, 2011] Exp: To prevent iron from rusting Galvanization, painting and applying Grease are beneficial but annealing is done in glass. Annealing of glass is the process of slowly cooling hot glass object after they have been formed to remove internal stresses.

Question 245

29.Potassium Permanganate is used for purifying drinking water, because_________ (A) It is a reducing agent(B) It is an oxidising agent (C) It is a sterilising agent (D) It dissolves the impurities of water

Answer 245

(B) (SSC CGL 2016) Exp: Potassium permanganate (KMnO4) is a powerful oxidising agent because it liberates nascent oxygen. An oxidizing agent or oxidant, gains electrons & is reduced in a chemical reaction. Oxidant is also known as the electron Acceptor. eg:- KMnO4, K2 Cr2 O7 are some examples of strong oxidizing agent.

Question 246

30.Carbon dioxide is (A) A Reducing agent (B) An Oxidising agent (C) A Dehydrating agent (D) A Bleaching agent

Answer 246

(B) [SSC Matric Level 2008] Exp: Carbondioxide is an oxidising agent because in Carbondioxide, Carbon has highest oxidation no. (+4). Oxidizing Agent is normally in one of its higher possible oxidation states because it will gain electrons & is reduced it self.

Question 247

31.The reactions in which oxidation and reduction occur simultaneously are called___. (A) Feral reactions (B) Redox reactions (C) Demug reactions (D) Kerol reactions

Answer 247

(B) (SSC CHSL 2016) Exp: Redox reactions are those chemical reactions in which oxidation and reduction takes place simult aneausly. Zn+Cu+2 Zn +Cu +2 oxidation Reduction

Question 248

32.Rusting is _____. (A) Electrolysis (B) Oxidation (C) Redox reaction (Oxidation and Reduction) (D) Reduction

Answer 248

(B) (SSC CGL 2017) Exp: Rusting is an oxidation process. The deposition of reddish brown layer of Fe2O3.xH2O on iron is called Rusting. Iron in presence of water vapour (Moisture) & oxygen form rust. 4Fe + 3O2 water vapour 2Fe2O3.xH2O

Question 249

33.Which among the following metal is used for galvanization? (A) Zinc (B) Copper (C) Iron (D) Silver

Answer 249

(A) (SSC CGL 2017) Exp: Galvanisation is a process in which coating of zinc on iron metal is done to prevent iron from rusting.

Question 250

34.Process of gaining electrons is known as _____. (A) Oxidation (B) Reduction (C) Radiation (D) Both oxidation and reduction

Answer 250

(B) (SSC CGL 2017) Exp: Process of gaining electrons is reduction. Reduction is defined as :- (1) Addition of Hydrogen (2) Removal of oxygen or electronegative element (3) Addition of electrons. (4) Decrease in oxidation number. eg :- Cl2+ e- 2 Cl- (0) (-1) oxidation no.

Question 251

35.Process of loosing electrons is known as _____. (A) Oxidation (B) Reduction (C) Radiation (D) Both oxidation and reduction

Answer 251

(A) (SSC CGL 2017) Exp: Process of loosing electrons or increase in oxidation state is called Oxidation. eg:- Mg Mg2+ + 2e- (0) (+2) (oxidation state)

Question 252

36.What is the process of rust forming on iron called? (A) Rusting (B) Crystallisation (C) Shovel (D) Spade

Answer 252

(A) (SSC CGL 2017) Exp: Rusting is the process of rust forming on iron. Rust is a reddish brown layer of Fe2O3. xH2O. Rust is formed when iron comes in contact with oxygen & moisture (water vapours).

Question 253

37.The process of deposition of a layer of zinc on iron is called ___________ . (A) Galvanisation (B) Crystallisation (C) Rusting (D) Baking

Answer 253

(A) (SSC CGL 2017) Exp: The process of deposition of a layer of zinc on Iron to prevent it from rusting is called Galvanization. It is one of the best method to prevent iron from corrosion or rusting.

Question 254

38.The process of deposition of a layer of any desired metal on another material by means of electricity is called ___________. (A) Electroplating (B) Galvanisation (C) Rusting (D) Crystallisation

Answer 254

(A) (SSC CGL 2017) Exp: The process of deposition of a layer of any desired metal on another material by means of electricity is called as Electroplating. It is done for decorative purpose or to prevent corrosion of metals. Eg:- copper plating, silver plating etc.

Question 255

39.Brownish film formed on iron when left in open is called? (A) Dust (B) Shovel (C) Spade (D) Rust

Answer 255

(D) (SSC CGL 2017) Exp: Process of deposition of reddish brown layer on iron in the presence of oxygen & moisture is called Rusting. The brown layer i.e. Fe2O3.xH2O is called rust.

Question 256

Which of the following is the strongest acid? (A) CF3COOH (B) CBr3COOH (C) CH3COOH (D) CCl3COOH

Answer 256

(A) Exp: CF3COOH is the strongest acid. Electronegative atom attracts the electron density towards itself so it decreases on O atom. To compensate electron density, O atom takes the electron from H atom by releasing H+ (Proton), i.e. called acidic nature. Strong acid is an acid which completely dissociated or ionised in aqueous solution. They have high capacity to loose proton.

Question 257

2.Which of the following is the weakest acid? (A) C6H5OH (B) CH3COOH (C) HCOOH (D) C6H5COOH

Answer 257

(A) Exp: Monocarboxylic acids are stronger than phenol. In carboxylate ion, the negative charge is dispersed on two electronegative oxygen atoms while in case of phenate ion, there is only one oxygen atom to disperse the negative charge. This means that there is more dispersal of negative charge in case of carboxylate ion than phenate ion. This shows that a carboxylic acid is stronger acid than phenol. Weak acid dissociates incompletely or release some H+ in solution. Weak acid has low capacity to loose proton.

Question 258

3.The element common to all acid is? (A) Hydrogen (B) Nitrogen (C) Oxygen (D) Sulphur

Answer 258

(A) Exp: Hydrogen is most common to all acids.

Question 259

4. Which acid is known as ‘King of chemicals’? (A) HCl (B) H2SO4 (C) HNO3 (D) H3PO4

Answer 259

(B) Exp: H2SO4 (Sulphuric acid) is known as king of chemicals.

Question 260

4.The — OH group of — COOH can be replaced by Cl using (A) PCl5 (B) HOCl (C) Cl2 (D) HCl

Answer 260

(A) Exp: The -OH group of -COOH can be replaced by Cl using PCl5, PCl3 or SOCl2. In the given options PCl5 is correct answer.

Question 261

5.Which is known as Carbolic acid? (A) Phenol (B) Ethanol (C) Acetic acid (D) Oxalic acid

Answer 261

(A) (SSC CGL 2016) Exp: Phenol (C6H5OH) is also known as hydroxyl benzene.

Question 262

6.Ammonium chloride is acidic salt, because it is a salt of:- (A) Weak acid and Weak base (B) Weak acid and Strong base (C) Strong acid and Weak base (D) Stong acid and Strong base

Answer 262

(C) Exp: Ammonium chloride is acidic salt because it is a salt of strong acid and weak base. HCl + NH4OH NH4Cl + H2O

Question 263

7.Choose the acid salt from the following? (A) NaNO3 (B) Na2SO4 (C) Na2CO3 (D) NaHSO4

Answer 263

(D) Exp: In the given options, option (D) is correct. NaHSO4 is an acidic salt because replaceable hydrogen is present in it.

Question 264

8.Acids turn _____ litmus to ______ (A) Red, Blue (B) Green, Yellow (C) Yellow, Green (D) Blue, Red

Answer 264

(D) (SSC CHSL 2016) Exp: Acid turns blue litmus to Red. Note: Methylorange becomes red in acid medium phenolphthalein remains colourless in acidic medium.

Question 265

9.Which among the following is false about acids? (A) They give H+ ions in aqueous solution (B) Most acids contain hydrogen (C) They turn blue litmus to red (D) They are bad conductor of electricity in aqueous solution

Answer 265

(D) Exp: In the given options, option (D) is false. Acids are good conductor of electricity in aqueous solution because acids ionise and produce free ions.

Question 266

10.Which of the following metals behaves as a non- metal towards concentrated HNO3? (A) Cu (B) Fe (C) Sn (D) Pb

Answer 266

(C) Exp: Sn + 4HNO3 (Conc.) H2SnO3+ 4NO2 + H2O (Stannic acid) or Sn + 4NO3 - + 2H+ 2 SnO3 - + H2O + 4NO2 In the above reaction, Sn behaves as a non-metal.

Question 267

11.Concentrated HNO3 is stored in containers made of: (A) Cu (B) Zn (C) Al (D) Si

Answer 267

(C) Exp: Since Al is rendered passive when put into conc. HNO3, the acid can be stored in containers made of Al. Passive nature of Al is due to the formation of a thin layer of Al2O3 on its surface.

Question 268

12.Skin becomes yellow in concentrated HNO3 because: (A) The proteins are converted into Xantho proteins (B) HNO3 acts as a dehydrating agent. (C) Nitrocellulose is formed (D) HNO3 acts as an oxidising agent

Answer 268

(A) Exp: Concentrated HNO3 attacks proteins of the skin, forming a yellow nitro compound with skin which is called Xantho protein.

Question 269

13.Which one of the following is strongest acid? (A) Acetic acid (B) Monocholoro acetic acid (C) Dichloro acetic acid (D) Trichloro acetic acid

Answer 269

(D) [SSC MTS 2006] Exp: In the given options Trichloro acetic acid is strongest acid due to maximum -I effect. As no. of electronegative atom increases, Acidic nature increases.

Question 270

14.Organic acid containing Hydroxyl group is - (A) Benzoic acid (B) Carbolic acid (C) Acetic acid (D) Cinnamic acid

Answer 270

(B) [SSC MTS 2006] Exp: In the given options only carbolic acid has -OH (Hydroxyl) group. It is commonly known as phenol. Compound Molecular Formula (A) Benzoic acid C6H5COOH (B) Carbolic acid C6H5OH (C) Acetic acid CH3COOH (D) Cinnamic acid C6H5CH = CHCOOH

Question 271

15.Sulphuric acid is - (A) Monobasic (B) Dibasic (C) Tribasic (D) Tetra basic

Answer 271

(B) [SSC CHSL 2013] Exp: Sulphuric acid is a dibasic acid because two replaceable hydrogen atoms are present. H2SO4 H+ + HSO4 - HSO4 - H++ SO4 2- O H- O - S - O - H O = = Note: Basicity of an Acid is defined as no. of replaceable hydrogen atoms present in one molecule of acid.

Question 272

16.The Chemical formula of Acetic acid is _____. (A) CH3COH (B) CH3COOH (C) CH3COCH3 (D) CH2COOH

Answer 272

(B) (SSC CHSL 2016) Exp: The Chemical formula of Acetic acid is CH3COOH

Question 273

17.Chemical name of vinegar is (A) Acetone (B) Acetic acid (C) Formaldehyde (D) Ethanol

Answer 273

(B) (SSC CGL 2016) Exp: Chemical name of vinegar is Acetic Acid or Ethanoic acid (CH3COOH). Vinegar is 5-10% dilute solution of Acetic Acid. It is used as a preservative.

Question 274

18.The acid used in the Lead storage cell is - (A) Phosphoric acid (B) Hydrochloric acid (C) Nitric Acid (D) Sulphuric acid

Answer 274

(D) [SSC Tax Asst. 2006] or

Question 275

Which one of the following acid is used in the battery? (A) Hydrochloric acid (B) Hydrofluoric acid (C) Sulphuric acid (D) None of these

Answer 275

(C) [SSC Tax Asst. 2007] or

Question 276

Which acid is used in Lead storage battery? (A) Sulphuric acid (B) Nitric acid (C) Hydrochloric acid (D) Acetic acid

Answer 276

(A) Exp: 38% of H2SO4 solution is used in lead storage battery. It works as an electrolyte.

Question 277

19.Which of the following does not contain a carboxylic group? (A) Picric Acid (B) Aspirin Acid (C) Benzoic Acid (D) Ethanoic Acid

Answer 277

(A) Exp: In the given options, Picric acid is only acid that does not contain carboxylic acid. Picric acid is used as an explosive. It is chemically 2,4,6-Trinitro phenol. OH O N2 NO2 NO2 Structure of Picric Acid

Question 278

20.Chemical name of ‘Oil of Vitriol is- (A) Sulphuric acid (B) Hydrochloric acid (C) Phosphoric acid (D) Nitric acid

Answer 278

(A) [SSC Steno 2012] Exp: Sulphuric acid (H2SO4) is also known as ‘Oil of V itr io l ‘ because this acid is oily and viscous in concentrated form.

Question 279

21.A fruity smell is produced by the reaction of C2H5OH with- (A) PCl5 (B) CH3COCH3 (C) CH3COOH (D) None of these

Answer 279

(C) Exp: A fruity smell is produced by the reaction of C2H5OH with CH3COOH. This reaction is known as Esterification. CH3COOH+C2H5OH H CH3COOC2H5+H2O Ethylacetate (Fruity smell)

Question 280

22.The compound used in prickly-heat powder to prevent excessive sweating is (A) Boric acid (B) Phosphoric acid (C) Carbonic acid (D) Sulphonic acid

Answer 280

(A) (SSC CGL 2016) Exp: Boric Acid (H3BO3) is used in prickly heat powder to prevent excessive sweat. It is a mild Antiseptic. It is not a protonic Acid but a Lewis acid.

Question 281

23.Name the source from which Aspirin is produced? (A) Willow bark (B) Oak Tree (C) Acacia (C) Eucalyptus

Answer 281

(A) (SSC CHSL 2016) Exp: Aspirin is produced from bark of willow tree. Aspirin was discovered by Felix Hoffmann.

Question 282

24.The acid used to dissolve gold is (A) Hydrochloric Acid (B) Aquaregia (C) Nitric Acid (D) Phosphoric acid

Answer 282

(B) Exp: Aqua regia is a mixture of conc. Nitric acid (HNO3) & conc. Hydrochloric acid (HCl) in a molar ratio of 1: 3. Aquaregia is a yellow orange fuming liquid which can dissolve the noble metals such as gold & platinum. It is also known as Royal acid.

Question 283

25.Baking soda is one of the constituents of baking powder. The other constituent is (A) Acetic Acid (B) HCl (C) Citric Acid (D) Tartaric Acid

Answer 283

(D) [SSC CHSL 2016] Exp: Baking powder is a mixture of baking soda (NaHCO3) and tartaric acid. Tartaric acid is found in grapes.

Question 284

26.Among these which acid is a strong dehydrating agent? (A) CH3COOH (B) H2SO4 (C) HCl (D) HNO3

Answer 284

(B) Exp: In the given options, H2SO4 is a strong dehydrating agent this is due to strong affinity for water. C12H22O11 H SO 2 4 12C+11H2O Sugar (sucrose) (absorbed by acid)

Question 285

28. Which one of the following is battery acid? (A) HCl (B) H2SO4 (C) HNO3 (D) H3PO4

Answer 285

(B) Exp: H2SO4 is used in lead storage battery so it is known as battery acid.

Question 286

29.Hydrochloric acid is also known as- (A) Galic acid (B) Picric acid (C) Muriatic acid (D) Chloric acid

Answer 286

(C) [SSC CHSL 2014] Exp: Hydrochloric acid was historically called as acidum salis, muriatic acid & spirits of salt.

Question 287

30.Among these which one is a mild acid (A) Hydrochloric Acid (B) Nitric Acid (C) Sulphuric Acid (D) Boric Acid

Answer 287

(D) Exp: Boric acid [H3BO3 or B (OH)3] is a mild acid. It is used to make eye lotion. It is used as an antiseptic. HCl, HNO3 & H2SO4 are strong acids.

Question 288

31.Which acid is present in apple? (A) Citric Acid (B) Acetic Acid (C) Malic Acid (D) None of these

Answer 288

(C) Exp: Malic acid is found in apples and hence its name is (L. malus = apple). It is used as acidulant in soft drinks and food stuffs. It is also used as a remedy for sore throat.

Question 289

32.Which acid is used for making Aspirin? (A) Acetic Acid (B) Salicyclic Acid (C) Succinic Acid (D) Oxalic Acid

Answer 289

(B) Exp: Aspirin (Acetylsalicylic acid) is prepared by heating salicyclic acid with acetyl chloride or acetic anhydride in the presence of phosphoric acid. It reduces fever. It is also used as a pain killer.

Question 290

33.Which acid is present in tomatoes? (A) Oxalic acid (B) Citric acid (C) Acetic acid (D) Malic acid

Answer 290

(A) Exp: Oxalic acid is present as potassium hydrogen oxalate in the tomatoes and spinach. Oxalic acid is used to remove iron rust stains from clothes.

Question 291

34.Which acid is used to remove Iron and rust stains from clothes? (A) Citric Acid (B) Dilute Hydrochloric Acid (C) Oxalic Acid (D) Acetic Acid

Answer 291

(C) Exp: Oxalic acid is used to remove iron rust stains from clothes.

Question 292

35.________ is used for making Vinegar. (A) Tartaric acid (B) Malic acid (C) Oxalic acid (D) Acetic acid

Answer 292

(D)Exp: Acetic acid is used for making vinegar. 5-10% dilute solution of acetic acid is known as vinegar. Note: 100% pure acetic acid is known as Glacial acetic acid.

Question 293

36.Which of the following induces souring of milk? (A) Acetic Acid (B) Citric Acid (C) Ascorbic Acid (D) Lactic Acid

Answer 293

(D) Exp: Lactic acid is the main constituent of milk that has gone sour so, lactic acid induces souring of milk.

Question 294

37.Name the acid present in lemon. (A) Phosphoric acid (B) Carbonic acid (C) Citric acid (D) Malic acid

Answer 294

(C) Exp: Citric acid is present in juices of citrus fruits such as lemons, galgals and oranges. Lemon juice contains 7- 10% Citric acid.

Question 295

38.Acetic acid is known as_____ (A) Caustic soda (B) Spirit (C) Baking soda (D) Vinegar

Answer 295

(D) Exp: Acetic acid is known as Vinegar. Acetic acid occurs in fruit juices which have become sour as result of fermentation.

Question 296

39.An Ester used as medicine is:- (A) Ethyl Acetate (B) Methyl Acetate (C) Methyl Salicylate (D) Ethyl Benzoate

Answer 296

(C) Exp: Methyl Salicylate is used in aid Sprays and ointments. It is also used in rheumatic pains. (For eg. Omnigel, Iodex, Volini gel). It is the principle constituent of Oil of wintergreen.

Question 297

40.Bee sting contains___________. (A) An acidic liquid (B) A salt solution (C) An-alkaline liquid (D) A corrosive liquid

Answer 297

(A) (SSC CGL 2016) Exp: Bee sting contains an acidic liquid known as formic acid. Formic acid is used in the preservation of fruits, as an antiseptic, in the treatment of gout.

Question 298

41.Vinegar is the common name of - (A) Acetic acid (B) Hydrochloric acid (C) Acid of Lemon (D) Oxalic acid

Answer 298

(A) [SSC MTS 2002, 1992, SSC CGL 2010] or Vinegar is (A) Diluted acetic acid (B) Glacial acetic acid (C) Glacial formic acid (D) Diluted formic acid (A) [SSC CGL 2016] Exp: Vinegar is dilute solution of 5-10% of acetic acid (CH3COOH).

Question 299

42.Which one of the following is found in Vinegar? (A) Lactic acid (B) Formic acid (C) Butyric acid (D) Acetic acid

Answer 299

(D) [SSC CPO 2015] Exp: Acetic acid is used for making vinegar. 5-10% dilute solution of acetic acid is known as Vinegar. Note: 100% pure acetic acid is known as Glacial acetic acid.

Question 300

43.Vinegar formed by the fermentation of cane sugar contains- (A) Palmitic acid (B) Lactic acid (C) Citric acid (D) Acetic acid

Answer 300

(D) [Tax Asst. 2008] Exp: Vinegar is formed by the fermentation of cane sugar. It contains acetic acid.

Question 301

44.If some drops of conc sulphuric acid is added to that substance then turns to black, which of the following is that substance? (A) Vinegar (B) Sugar (C) Food salt (D) Alcohol

Answer 301

(B) [SSC Steno 2014] Exp: If some drops of conc. H2SO4 is dropped on sugar then initially it gets converted into light brown colour and then converted into black by the following chemical equation. C12 H22O11 + H2SO4 12C + 11H2O (sugar) (Conc. Sulp- (carbon) (water) huric acid) This is also the method of obtaining carbon from carbohydrate.

Question 302

45.Match the source of column B with the product of column A- Column A Column B (Product) (Source) A. Formic acid 1. Lemon B. Citric Acid 2. Tamarind C. Tartaric Acid 3. Ants A B C (A) 3 2 1 (B) 3 1 2 (C) 2 3 1 (D) 2 1 3

Answer 302

(B) [SSC Tax Asst 2007] Exp: Formic acid-Ants, Citric acid-lemon, Tartaric acid- Tamarind

Question 303

46.The acid which fails to liberate carbon dioxide from Sodium bicarbonate is - (A) Sulphuric acid (B) Formic acid (C) Carbonic acid (D) Acetic acid

Answer 303

(C) [SSC GD 2015] Exp: Carbonic acid cannot liberate the carbon dioxide from sodium bicarbonate. NaHCO3 + CH3COOH CH3COONa + CO2 + H2O NaHCO3 + HCOOH HCOONa + CO2 + H2O 2NaHCO3 + H2SO4 Na2SO4 + 2H2O + 2CO2

Question 304

47.Sour taste of coca cola is due to- (A) Acetic acid (B) Phosphoric acid (C) Hydrochloric acid (D) Formic acid

Answer 304

(B) [SSC CPO Exam, 2006] Exp: Sour taste of coca cola is due to the existence of phosphoric acid it is used as flavoring agent in manufacturing of soft drinks.

Question 305

48.Which one of the following is used to dissolve noble metals? (A) Nitric acid (B) Hydrochloric acid (C) Sulphuric acid (D) Aqua regia

Answer 305

(D) Exp: Aquaregia is used to dissolve noble metals like platinum, gold etc.

Question 306

49.Aqua regia is a Mixture of the following in the ratio 1:3 by volume- (A) Conc HNO3 and conc HCl (B) Conc HNO3 and Conc H2SO4 (C) Dil HCl and Conc HNO3 (D) Conc HCl and Conc HNO3

Answer 306

(A) Exp: Aquaregia is a mixture of conc. HNO3 and conc. HCl in ratio 1: 3.

Question 307

50.Sour taste of lemon is due to the presence of which of the following? (A) Citric acid (B) Acetic acid (C) Oxalic acid (D) Formic acid

Answer 307

(A) (SSC CGL 2016) Exp: Citric acid is found in the juice of citrus fruits such as lemons, limes, galgals and oranges. Lemon juice contains 7-10% citric acid.

Question 308

51.Which chemical is injected into a person’s body when an ant bites? (A) Formic Acid (B) Acetic Acid (C) Tartaric Acid (D) Citric Acid

Answer 308

(A) (SSC CHSL 2016) Exp: Formic acid (HCOOH) is injected into a person’s body when red ant bites.

Question 309

52.Formic acid is produced by_______. (A) White ants (B) Cockroaches (C) Red ants (D) Mosquitoes

Answer 309

(C) (SSC CGL 2016) Exp: Formic Acid is produced by red ants. It is used in treatment of gout.

Question 310

53.Sodium carbonate is basic salt, because it is a salt of: (A) Weak acid and Weak base (B) Strong acid and strong base (C) Weak acid and strong base (D) Strong acid and weak base

Answer 310

(C) Exp: Sodium carbonate is basic salt, because it is a salt of weak acid and strong base. H2CO3 + 2NaOH Na2CO3 + 2H2O

Question 311

54.Among these which one is not a Base? (A) Ba(OH)2 (B) Sr(OH)2 (C) B(OH)3 (D) Ca(OH)2

Answer 311

(C) Exp: In the given options B(OH)3 is not a base. B(OH)3 is not a protonic acid but acts as a lewis acid by accepting electrons from a hydroxyl ion. B(OH)3+2HOH B OH H O 4 3 -

Question 312

55.The Base used as an antacid is - (A) Calcium Hydroxide (B) Barium Hydroxide (C) Magnesium Hydroxide (D) Silver Hydroxide

Answer 312

(C) [SSC CGL 2012] Exp: Magnesium Hydroxide is used as an antacid, it neutralize the acidity of stomach. It is called as Milk of Magnesia.

Question 313

56.The natural indicator is- (A) Phenolphthalein (B) Litmus (C) Methyl Orange (D) All of these

Answer 313

(B) Exp: In the given options litmus is natural indicator. Litmus is obtained from Lichens.

Question 314

57.Litmus is obtained from- (A) A bacterium (B) A fungus (C) An alga (D) Lichen

Answer 314

(D) [SSC Tax Asst. 2008] Exp: Litmus is obtained from Rochella lichen. Litmus solution is a natural indicator. The substances that undergo a definite colour or odour change in presence of acids and bases are called Indicators.

Question 315

58.pH value of Human blood is (A) 8.25 - 8.35 (B) 7.35 - 7.45 (C) 6.45 - 6.55 (D) 4.0 - 4.5

Answer 315

(B) Exp: pH value of human blood is 7.35 - 7.45. Blood is alkaline in nature. Human blood contains a buffer of carbonic acid (H2CO3) and bicarbonate ion 3 HCO- in order to maintain blood pH. pH value of higher than 7.8 or lower than 6.8 can lead to death.

Question 316

59.What is the pH of water? (A) 7 (B) 5 (C) 3 (D) 1

Answer 316

(A) Exp: Pure water is neutral in nature so its pH value will

Question 317

60. pH-scale ranges from - (A) 0-7 (B) 8-14 (C) 0-14 (D) None of these

Answer 317

(C) [SSC CGL Exam, 2014] Exp: pH scale ranges from 0-14. pH scale was discovered by H. sorenson. This scale is used to identify the nature of solution, whether it is acidic, basic or neutral. for Acidic solution, pH < 7 for Basic solution, pH > 7 for Neutral solution, pH = 7

Question 318

60.The pH of Lemon Juice is expected to be- (A) Nothing can be predicted (B) Less than seven (C) More than seven (D) Equal to seven

Answer 318

(B) [SSC CHSL 2013] Exp: Lemon contains citric acid so the pH of lemon Juice is expected to be less than seven. The pH level of lemon juice is 2.

Question 319

61.Aluminium oxide is a/an? (A) Basic oxide (B) Neutral oxide (C) Amphoteric (D) Acid Oxide

Answer 319

(C) Exp: Aluminium oxide is an amphoteric oxide because it behaves as an acid in the presence of base and behaves as base in the presence of an acid. Al2O3 + 6HCl 2AlCl3 + 3H2O Al2O3 + 2NaOH + 3H2O 2NaAlO2 + 4H2O Sodium meta Aluminate

Question 320

62.The drying of milk of lime (white washing) is due to the action of _________ (A) CO2 in air (B) Oxygen in air (C) CO in air (D) Hydrogen in air

Answer 320

(A) Exp: The drying of milk of lime (white washing) is due to the action of CO2 in air. Ca(OH)2 + CO2 CaCO3+H2O

Question 321

63.Soda water was invented by (A) Tivadar Puskas (B) Joseph Priestley (C) Petrache Poenaru (D) James Leonard Plimpton

Answer 321

(B) (SSC CHSL 2016) Exp: Soda water was invented by Joseph priestly. It is also known as carbonated water. CO2 gas is also used in soda water.

Question 322

64.Kidney stones are composed of ______. (A) Calcium Oxalate (B) Sodium Chloride (C) Magnesium Nitrate(D) Calcium Bicarbonate

Answer 322

(A) (SSC CHSL 2016) Exp: Kidney stones are composed of calcium oxalate. It is a salt of oxalic acid.

Question 323

65.Nitric acid does not react with (A) Gold (B) Copper (C) Zinc (D) Iron

Answer 323

(A) (SSC CGL 2016) Exp: Nitric Acid does not react with gold and platinum (noble metals) Fe + 6HNO3 Fe(NO3) 3+ 3NO2 + 3H2O Cu + 4HNO3 Cu(NO3) 2 + 2NO2 + 2H2O Zn + 4HNO3 Zn(NO3) 2 + 2H2O + 2NO2

Question 324

66.Iodex, a pain relief balm, has the smell of ___________. (A) Methyl salicylate (B) Ethyl salicylate (C) Propyl salicylate (D) Butyl salicylate

Answer 324

(A) (SSC CGL 2016) Exp: Iodex has the smell of methyl salicylate (oil of wintergreen). It is used in ointments (eq- omnigel volini gel) for treating aches, sprains and bruises.

Question 325

67.What is Brine solution? (A) Excess salt + water (B) Silver (C) Excess Ethanol + water (D) Excess starch + water

Answer 325

(A) (SSC CPO 2017) Exp: Brine is a solution of excess salt & water (NaCl + H2O). Brine is also called as salt water.

Question 326

68.pH scale ranges from _____ . (A) 1 to 14 (B) 1 to 7 (C) 0 to 14 (D) 0 to 7

Answer 326

(C) (SSC CPO 2017) Exp: pH scale ranges from 0-14. The degree of the acidity or the alkalinity of a solution is measured on a scale which is called as pH scale. For Acidic solution, pH value is less than 7. For Basic solution, pH value is above 7. For neutral solution, pH value is 7. Eg:- Distill water.

Question 327

69.Sodium bicarbonate is chemical name of which of the following? (A) Baking Soda (B) Washing Powder (C) Plaster (D) Fly-Ash

Answer 327

(A) (SSC CPO 2017) Exp: Sodium bicarbonate is the chemical name of Baking Soda (NaHCO3). It is used in cooking. When it is heated, it gives out CO2 which is responsible for fluffy & light texture of bread. 2 NaHCO3 (s) Na2CO3 (s) + CO2 (g) + H2O (g)

Question 328

70.Which among the following is a pure element? (A) Glass (B) Cement (C) Sodium (D) Steel

Answer 328

(C)Exp: Sodium is a pure element. Glass is a mixture of sand, lime & soda. Cement is a mixture of limestone, clay, silica & alumina. Steel is an alloy of manganese, nickel, iron chromium & carbon etc.

Question 329

71.Which among the following is responsible for colour of nitric acid? (A) Carbon dioxide (B) Sulphur dioxide (C) Coloured impurities(D) Nitrogen dioxide

Answer 329

(D) (SSC CPO 2017) Exp: Yellowish brown colour of HNO3 is due to Nitrogen dioxide which is formed by partial decomposition of HNO3 acid. 4HNO3 2 H2O + 4NO2 + O2

Question 330

72.Match the following pair:- Nature Substance 1. Acidic (a) Distill water 2. Basic (b) Carbonated drink 3. Neutral (c) Soap (A) 1 - a, 2 - c, 3 - b (B) 1 - b, 2 - c, 3 - a (C) 1 - a, 2 - b, 3 - c (D) 1 - c, 2 - a, 3 - b

Answer 330

(B) (SSC CPO 2017) Exp: Nature Substance 1. Acidic (a) Carbonated drink 2. Basic (b) Soap 3. Neutral (c) Distill water Carbonated drink is Acidic in nature due to presence of H2CO3 acid. Soaps are Sodium or Potassium salts of fatty acids, which provide basic nature. Distill water has no salts or impurity so it is neither acidic nor basic i.e. neutral.

Question 331

73.’Oil of vitriol’ is the common name of which of the following? (A) Nitric Acid (B) Carbonic Acid (C) Acetic Acid (D) Sulphuric Acid

Answer 331

(D) (SSC CPO 2017) Exp: Sulphuric acid is also known as ‘Oil of vitriol’ because this acid is oily & viscous in concentrated form.

Question 332

74.Which among the following acid is also known as ‘Muriatic Acid’? (A) Hydrochloric Acid (B) Sulphuric Acid (C) Carbonic Acid (D) Nitric Acid

Answer 332

(A) (SSC CPO 2017) Exp: Hydrochloric acid is also known as Muriatic acid, acidum & spirit of salt.

Question 333

75.What is the chemical name of vinegar? (A) Acetic Acid (B) Citric Acid (C) Lactic Acid (D) Formic Acid

Answer 333

(A) (SSC CPO 2017) Exp: Chemical name of Vinegar is Acetic Acid or Ethanoic acid (CH3COOH). Vinegar is 5-10% dilute solution of Acetic acid. It is used as preservative.

Question 334

76.What is the common name of Calcium Hypochlorite? (A) Water (B) Bleaching powder (C) Baking soda (D) Baking powder

Answer 334

(B) (SSC CPO 2017) Exp: Calcium Hypochlorite is bleaching powder. Its chemical formula is CaOCl2. It is used in disinfection of water & as a bleaching agent.

Question 335

77.Spinach contains _____. (A) Lactic Acid (B) Oxalic Acid (C) Carbonic Acid (D) Formic Acid

Answer 335

(B) (SSC CPO 2017) Exp: Leafy vegetables contain Oxalic acid & Spinach has the highest level of Oxalic acid 750 mg per 100 g. Spinach is very good source of Vitamin A.

Question 336

78.What is the common name of sodium carbonate? (A) Limestone (B) Lime (C) Marble (D) Washing soda

Answer 336

(D) (SSC CPO 2017) Exp: Washing Soda is sodium carbonate decahydrate (Na2CO3.10H2O). It is disodium salt of Carbonic acid with alkaline nature.

Question 337

79.Washing soda is chemically called as _____. (A) Sodium carbonate (B) Sodium chloride (C) Sodium hydroxide (D) Potassium nitrate

Answer 337

(A) (SSC CPO 2017) Exp: Washing Soda is sodium carbonate decahydrate (Na2CO3.10H2O). It is disodium salt of Carbonic acid with alkaline nature.

Question 338

80.Tartaric Acid is not found in _____. (A) Tamarind (B) Grapes (C) Unriped mangoes (D) Spinach

Answer 338

(D) (SSC CPO 2017) Exp: Tartaric acid is found in tamarind, Grapes & unriped mangoes. While oxalic acid is present in Spinach.

Question 339

81.What is the chemical name of quick lime? (A) Calcium carbonate (B) Sodium hydroxide (C) Calcium oxide (D) Calcium sulphate

Answer 339

(C) (SSC CPO 2017) Exp: Chemical name of quick lime is Calcium Oxide (CaO). It reacts with water to form slaked lime. CaO + H2O Ca(OH)2.

Question 340

82.What is the common name of CaOCl2? (A) Washing soda (B) Bleaching powder (C) Baking powder (D) Baking soda

Answer 340

(B) (SSC CPO 2017) Exp: Calcium Hypochlorite is bleaching powder. Its chemical formula is CaOCl2. It is used for disinfection of water & bleaching purpose.

Question 341

83.What is the nature of antacid? (A) Acidic (B) Basic (C) Neutral (D) Highly Acidic

Answer 341

(B) (SSC CPO 2017) Exp: The antacids are basic substances which on ingestion, decrease the stomach acidity by reacting with gastric acid. eg:- Milk of Magnesia [Mg(OH2)], Al2O3 & NaHCO3 etc.

Question 342

84.Oxide of which of the following will turn red litmus blue? (A) Magnesium (B) Phosphorous (C) Sulphur (D) Carbon

Answer 342

(A) (SSC CGL 2017) Exp: Generally, Metallic oxides are basic in nature while non metallic oxides are acidic in nature because on reacting with water they form base and acid respectively. Magnesium is only metal in given options so it will form oxide i.e. basic in nature & convert red litmus to blue. While phosphorous, Sulphur & carbon are non-metals. They will form acidic oxides.

Question 343

85.In the following reaction, fill in the blank. Acid + Base _______ + Water (A) Carbon dioxide (B) Metal Oxide (C) Hydrogen gas (D) Salt

Answer 343

(D) (SSC CGL 2017) Exp: Acid + Base Salt + water When an acid reacts with base, then water & salt are formed as product. This reaction is called as Neutralisation Reaction. eg:- NaOH + HCl NaCl + H2O (Base) (Acid) (Salt) (Water)

Question 344

86.pH of the human blood is ______. (A) Slightly acidic (B) Highly acidic (C) Slightly basic (D) Highly basic

Answer 344

(C) (SSC CGL 2017) Exp: pH of human blood is 7.35 to 7.5. So, pH is slightly alkaline or slightly basic.

Question 345

87.What is the chemical formula for Sodium Chloride (Salt)? (A) NaCl2 (B) NaCl (C) Na2Cl (D) Na2C

Answer 345

(B) (SSC CGL 2017) Exp: The chemical formula of sodium chloride is NaCl. It is main constituent of salt. It is also known as table salt or rock salt.

Question 346

88.What is nature of pH of Milk? (A) Slightly acidic (B) Slightly basic (C) Highly acidic (D) Highly basic

Answer 346

(A) (SSC CGL 2017) Exp: Due to presence of lactic acid in milk. Lactic acid is weak acid so, its pH value is less than 7 or slightly acidic.

Question 347

89.What is the common name of CaOCl2? (A) Baking powder (B) Baking soda (C) Bleaching powder (D) Washing soda

Answer 347

(C) (SSC CGL 2017) Exp: Common name of CaOCl2 is bleaching powder. In presence of dilute acids, it gives nascent oxygen, so it acts as oxisidising or bleaching agent. 2CaOCl2 + H2SO4 CaCl2 + CaSO4 + 2HOCl 2HOCl 2HCl + 2[O]

Question 348

90.What is the common name of Sodium bicarborate? (A) Baking soda (B) Washing powder (C) Plaster of paris (D) Fly ash

Answer 348

(A) (SSC CGL 2017) Exp: Baking soda is Sodium bicarbonate (NaHCO3). It is used in baking industry because on heating it releases CO2 which makes bread spongy & fluffy. 2 NaHCO3 Na2CO3 + CO2 + H2O

Question 349

91.Which of the following is a chemical formula of quicklime? (A) Ca2O (B) Ca2CO3 (C) CaO2 (D) CaO

Answer 349

(D) (SSC CGL 2017) Exp: Chemical formula of quicklime is CaO (calcium oxide). When it reacts with water, it forms slaked lime. CaO + H2O Ca(OH)2

Question 350

92.Most liquids that conduct electricity are solutions of acids, bases and ______. (A) Copper (B) Aluminium (C) Salts (D) Iron

Answer 350

(C) (SSC CGL 2017) Exp: Most liquids that conduct electricity are solutions of acids, bases & salts, because they contain ions

Question 351

93.Which base is present in milk of magnesia? (A) Magnesium hydroxide (B) Ammonium hydroxide (C) Sodium hydroxide (D) Calcium hydroxide

Answer 351

(A) (SSC CGL 2017) Exp: Magnesium hydroxide [Mg(OH)2] is called as Milk of Magnesia. It is used as an antacid which on ingestion, decreases the stomach acidity.

Question 352

94.What is the name of the acid in an ant’s sting? (A) Acetic acid (B) Citric acid (C) Formic acid (D) Lactic acid

Answer 352

(C) (SSC CGL 2017) Exp: Formic acid (HCOOH) or methanoic acid is present in red ant’s sting

Question 353

95.Which base is present in lime water? (A) Sodium hydroxide (B) Magnesium hydroxide (C) Calcium hydroxide (D) Ammonium hydroxide

Answer 353

(C) (SSC CGL 2017) Exp: Calcium hydroxide [Ca(OH)2] is present in lime water. It is also called as slaked lime It is formed by reaction of quick lime (CaO) & water. CaO+ H2O Ca(OH)2

Question 354

96.What is the reaction between an acid and a base called? (A) Desalination (B) Crystallisation (C) Neutralisation (D) Sublimation

Answer 354

(C) (SSC CGL 2017) Exp: Acid + Base Salt + Water When an acid reacts with base, salt & water are formed as product. This process is called as Neutralisation reaction. eg:- Ca(OH)2 + 2HCl CaCl2 + 2H2O (Base) (Acid) (Salt) (Water)

Question 355

97.In an acid base reaction which product is produced along with a salt? (A) Hydrogen gas (B) Oxygen gas (C) Carbon dioxide (D) Water

Answer 355

(D) (SSC CGL 2017) Exp: Acid + Base Salt + water When an acid reacts with base, then water & salt are formed as product. This reaction is called as Neutralisation Reaction. eg:- NaOH + HCl NaCl +H2O (Base) (Acid) (Salt) (Water)

Question 356

98.What is the name of the acid in grapes? (A) Lactic acid (B) Formic acid (C) Acetic acid (D) Tartaric acid

Answer 356

(D) (SSC CGL 2017) Exp: Tartaric acid is found in bananas, grapes & tamarind. It is added to food when a sour taste is desired.

Question 357

99.Blue Vitriol is another name for which of the following? (A) Copper Sulphate (B) Oxygen (C) Copper (D) Magnesium oxide

Answer 357

(A) (SSC CGL 2017) Exp: Blue vitriol is another name of CuSO4.7H2O. It is water soluble. It is blue in colour. It is used as an insecticide & fungicide.

Question 358

100.Acetic acid is another name for which of the following? (A) Vinegar (B) Baking soda (C) Copper sulphate (D) Magnesium oxide

Answer 358

(A) (SSC CGL 2017) Exp: Acetic acid is another name of vinegar. Vinegar is 5-10% dilute solution of Acetic acid It is used as preservative.

Question 359

101.The reaction of Copper Sulphate and Iron produces Iron Sulphate and __________. (A) Vinegar (B) Ash (C) Baking Soda (D) Copper

Answer 359

(D) (SSC CGL 2017) Exp: CuSO4 + Fe FeSO4 + Cu When CuSO4 reacts with iron, ferrous sulphate & copper are formed as product. This is a displacement reaction because high reactive metal (iron) displaces the copper from its salt.

Question 360

102.Crystallisation is an example of? (A) Physical change (B) Chemical change (C) Chemical reaction (D) Galvanisation

Answer 360

(A) (SSC CGL 2017) Exp: The formation of crystals (solid form) from homogeneous solution is called as Crystallisation. This process is a physical change as only liquid state is converted into solid state. There is no chemical reaction

Question 361

103.Vinegar and Baking Soda together produce ____________. (A) Copper (B) Carbon dioxide (C) Copper sulphate (D) Magnesium oxide

Answer 361

(B) (SSC CGL 2017) Exp: CH3COOH + NaHCO3 CH3COONa + H2O + CO2 Vinegar & Baking soda react together to form Carbon dioxide, water & sodium acetate

Question 362

104.Chemical formula for sulphurous acid is: (A) H2SO4 (B) H2SO3 (C) H3SO3 (D) H3SO4

Answer 362

(B) (SSC CGL 2017) Exp: Chemical formula for sulphurous acid is H2SO3. It is an aqueous solution of sulphur dioxide. It is weak & unstable acid. H2O + SO2 H2SO3

Question 363

1.Formation of cation occurs by- (A) Gain of electron (B) Loss of electron (C) Gain of proton (D) Loss of proton

Answer 363

(B) Exp: Formation of cation occurs by loss of electron. eg. Mg Mg+2 + 2e- Element/Ion No. of electrons Magnesium (Mg) 12 Magnesium ion (Mg2+) 10

Question 364

2.Formation of anions occurs by- (A) Loss of neutrons (B) Gain of protons (C) Gain of electrons (D) None

Answer 364

(C) Exp: Formation of anion occurs by gain of electrons. eg. Cl + e- Cl- Element/Ion No. of electrons Chlorine atom (Cl) 17 Chloride ion (Cl-) 18

Question 365

3.A bond formed by the transfer of electrons between atoms of the elements is called (A) Ionic-bond (B) Covalent bond (C) Co-ordinate bond (D) Hydrogen bond

Answer 365

(A) Exp: Ionic or electrovalent bond is formed by the complete transfer of electrons from one atom to another atom Eg. Ca O.. .. Ca +2 .. O. . .. .. -2

Question 366

4.Ionic solids are characterised by (A) Good conductivity in solid state (B) Low melting point (C) Solubility in polar solvent (D) High vapour pressure

Answer 366

(C) Exp: Ionic Solids (compounds) are generally soluble in water and other polar solvents having high dielectric constants. This is due to larger electrostatic interactions between polar solvents and ions.

Question 367

5.The compound which contains ionic bond is (A) CH4 (B) CHCl3 (C) NaCl (D) O2

Answer 367

(C)Exp: NaCl compound has ionic bond. In NaCl compound transfer of electron takes place from Na to Cl atom.— Na Cl.. .. Na + .. - . Cl. . .. .. .

Question 368

6.With reference to ionic compounds, consider the following statement: 1. Ionic compounds are soluble in alcohol 2. Ionic compounds in the solid state are good conductor of electricity Which of these statements is/are correct? (A) Only 1 (B) Only 2 (C) Both 1 and 2 (D) Neither 1 nor 2

Answer 368

(A) Exp: Ionic Compounds are soluble in alcohol because alcohols are polar in nature and ionic compounds are soluble in polar solvents. Ionic compounds don’t conduct electricity in solid state due to absence of free ions. Ions are bound together by strong electro-static force of attraction.

Question 369

7.Why do atoms form bond? (A) To reduce potential energy and gain stability (B) To make molecules (C) To increase potential energy and lose stability (D) To increase potential energy and gain stability

Answer 369

(A) (SSC CHSL 2016) Exp: Atoms form chemical bond to reduce potential energy of system and gain stability.

Question 370

8.Electrons in the highest energy level of a atom are called (A) Valence protons (B) Orbital protons (C) Valence electrons (D) Orbital electrons

Answer 370

(C) Exp: Electrons present in the highest energy level or outer most shell of an atom are called valence electrons. Only these electrons participate in chemical bonding.

Question 371

9.NaCl has ______. (A) Nonpolar bond (B) Polar covalent bond (C) Metallic bond (D) Ionic bond

Answer 371

(D) (SSC CHSL 2016) Exp: NaCl has ionic bond because there is a transfer of electron from Na atom to Cl atom takes place. Na× Cl Na × Cl

Question 372

10.A bond formed by sharing of electrons between atoms of the elements is called- (A) Ionic bond (B) Covalent bond (C) Co-ordinate bond (D) None

Answer 372

(B) Exp: Covalent bond is formed by mutual sharing of electrons between two or more atoms. Eg. H2 H.. H, H - H Note- Covalent bond is also known as Molecular bond.

Question 373

11.The compound which has covalent bond is (A) CsCl (B) CaO (C) N2 (D) Na2O

Answer 373

(C) Exp: N2 has triple Covalent bond. N N . . . . .. . .. . N N

Question 374

12.Double bond occurs in- (A) CH4 (B) C2H6 (C) C2H4 (D) C2H2

Answer 374

(C) Exp: Double bond occurs in C2H4

Question 375

13.Example of covalent bond is- (A) KCl (B) BaO (C) CHCl3 (D) CaO

Answer 375

(C) Exp: Covalent bond is present in CHCl3 H C Cl Cl Cl

Question 376

14.Ethylene is a ______ molecule. (A) Polar (B) Ionic (C) Covalent (D)Non-polar

Answer 376

(D) [SSC CGL 2016] Exp: Ethylene is non-polar molecule as it has Zero dipole moment (= 0).

Question 377

15.Compound having tetrahedral structure is- (A) C2H4 (B) C2H2 (C) CH4 (D) None

Answer 377

(C) Exp: CH4 (Methane) has tetrahedral structure. H C H H H

Question 378

16.The octet rule is not valid for which one of the following molecule- (A) CO2 (B) H2S (C) NH3 (D) BF3

Answer 378

(D) [SSC CPO 2014] Exp: The Octet rule is not valid for BF3 molecule. In BF3 molecule B atom has 6 electrons. F B F F 6e-

Question 379

17.The geometry of CCl4 is- (A) Tetrahedral (B) Triangular (C) Linear (D) Octahedral

Answer 379

(A) Exp: CCl4 molecule has tetrahedral geometry. Cl Cl C Cl Cl

Question 380

18. The structure of Ethylene is- (A) Linear (B) Tetrahedral (C) Octahedral (D) Triangular

Answer 380

(A) Exp: The Structure of Ethylene (Ethene) is linear. CH2 = CH2

Question 381

18.The (O-H) bond in CH3OH is _____. (A) Polar covalent (B) Ionic (C) Non polar covalent (D) Cationic

Answer 381

(A) (SSC CHSL 2016) Exp: The (O-H) bond in CH3OH is Polar Covalent due to electronegativity difference between Oxygen and Hydrogen atoms.

Question 382

19.Which has covalent bond? (A) Na2S (B) AlCl3 (C) NaH (D) MgCl2

Answer 382

(B) Exp: Alkali metals and Alkaline earth metals form ionic bond while Aluminium forms covalent bond with Cl. So AlCl3 molecule has covalent bond.

Question 383

20.Which of the following contains both ionic and covalent bond? (A) H2O (B) NaOH (C) C6H6 (D)CO2

Answer 383

(B) Exp: NaOH molecule contains both ionic and covalent bond. In NaOH molecule Na has positive charge while OH has negative charge. Ionic bond is present between Na+ & OH-. Covalent bond is present between O & H atoms in OH-.

Question 384

21.Which of the following compound is non-polar? (A) HCl (B) CH2Cl2 (C) CHCl3 (D) CCl4

Answer 384

(D) [SSC CGL 2014] Exp: CCl4 molecule is non polar this is due to regular tetrahedral structure and dipole moment is zero.

Question 385

22.Mark the compound which possesses ionic, covalent and co-ordinate bonds (A) SO2 (B) H2O (C) NH4Cl (D) CCl4

Answer 385

(C) Exp: NH4Cl molecule has ionic, covalent and Co-ordinate bond. Ionic bond is present between NH4 + ion and Cl- ion while covalent and co-ordinate bond is present in NH4 ion.

Question 386

23.Strongest bond is- (A) C = C (B) C C (C) C - C (D) all are equally strong

Answer 386

(B) Exp: Bond energy values for C-C, C = C & C C are 346, 598, 813 KJ respectively. So, C C is strongest.

Question 387

24.An example of a covalent molecule is- (A) Potassium chloride (B) Sodium chloride (C) Lead chloride (D) Carbon tetrachloride

Answer 387

(D) [SSC 2013] Exp: Carbon tetra chloride (CCl4) is an example of a covalent molecule. Covalent bond is formed by mutual sharing of electrons between C and Cl Atoms.

Question 388

25.Which of the following bonds will be the most polar? (A) N- Cl (B) O -F (C) C-F (D) N-N

Answer 388

(C) Exp: Since F-atom which is the most electronegative atom is present in (B) and (C), the correct answer will be out of these two alternatives. Since electronegativity of O atom is greater than that of C-atom, (xF - xC) is greater than (xF - xO) and hence F - C bond will be the most polar.

Question 389

26.Which of the following will be the least soluble in water? (A) NaCl (B) Na2S (C) MgCl2 (D) MgS

Answer 389

(D) Exp: We know that the Na+ ion is larger in size than Mg2+ (Na+ > Mg2+). Similary, S2- ion is also larger in size than Cl- ion (S2- > Cl-). Now MgS has smaller cation and larger anion, it would be the most covalent (Fajan’s rules) and hence would be the least soluble in water.

Question 390

27.Ethyne is an Example of compound- (A) Triple bond (B) Single bond (C) Double bond (D) Co-ordinate bond

Answer 390

(A) [SSC MTS 2014] Exp: Ethyne or Acetylene is an unsaturated hydrocarbon. It has triple bond between carbon -carbon atoms. Structure of Ethyne:- CH CH

Question 391

28.Which one of the following has a covalent bond? (A) Calcium Chloride (B) Magnesium Fluoride (C) Sodium chloride (D) Carbon Tetrachloride

Answer 391

(D) [SSC MTS 2014] Exp: In Covalent compounds, bond is formed between two or more nonmetals by mutual sharing of electrons. For Example: CCl 4, H2O, CO2 etc. Alkali & Alkaline Earth Metals form ionic bond.

Question 392

29.Which of the following molecules, is joined by a double covalent bond? (A) Cl2 (B) O2 (C) N2 (D) He2

Answer 392

(B) (SSC CHSL 2016) Exp: O2 molecule is joined by a double covalent bond. This double bond is formed due to mutual sharing of two electron pair. x x x x x x x x x x x x

Question 393

30.Why does carbon tetrachloride have no dipole moment? (A) Because of same size of carbon and chlorine atoms (B) Because of regular tetrahedral structure (C) Because of planar structure (D) Because of similar electron affinities of carbon and chlorine

Answer 393

(B) (SSC CHSL 2016) Exp: Because of regular tetrahedron structure, bond polarity is cancelled so, carbon tetrachloride (CCl4) has no dipole moment. Dipole moment can be defined as the product of the magnitude of the charge and the distance between the centres of positive and negative charge. Dipole moment (u) = charge (q) × distance of separation (r) It is expressed in debye units (D).

Question 394

31._____ is a polar covalent bond. (A) P-Cl (B) Ne-Cl (C) Cl-Cl (D) Ca-Cl

Answer 394

(A) (SSC CHSL 2016) Exp: P - Cl is a polar covalent bond due to higher electronegativity of chlorine than that of phosphorous.

Question 395

33. Covalent Bond is also called _________. (A) Molecular Bond (B) Proton Bond (C) Nucleus Bond (D) Electron Bond

Answer 395

(A) (SSC CHSL 2016) Exp: Covalent bond is also called Molecular bond. Covalent bond is defined as a chemical bond that involves the sharing of electron pairs between atoms. Shared electron pairs are known as bond pairs.

Question 396

34.Sulphur and Chlorine can have what type of a bond? (A) Polar covalent (B) Polyionic (C) Nonpolar (D) Ionic

Answer 396

(A) (SSC CHSL 2016) Exp: Bond formed between sulphur and chlorine is polar covalent bond because chlorine is more electronegative than sulphur and mutual sharing of electrons takes place between S and Cl.

Question 397

35._________ bond holds the atoms together within a water molecule. (A) Nonpolar covalent (B) Polar covalent (C) Ionic (D) Co-ordinate

Answer 397

(B) (SSC CHSL 2016) Exp: The polar covalent bond is formed when the atoms share the electrons unequally between each other due to electronegativity difference between O & H atom. This results in partial positive and negative charges on each atom. O H H ¶- ¶+ ¶+

Question 398

36.______ character of a bond between two atoms is greater if the difference in their electro negativities is lesser. (A) Polar (B) Metallic (C) Ionic (D) Covalent

Answer 398

(D) (SSC CHSL 2016) Exp: Ionic and covalent character describe the nature of the bond between atoms. The lesser the difference in electronegativity between the atoms, the greater the covalent character of the bond. The greater the difference in electronegativity between the atoms, the greater the ionic character of the bond.

Question 399

37.How many lone pair of electrons are present in N2? (A) 1 (B) 3 (C) 4 (D) 2

Answer 399

(D) (SSC CHSL 2016) Exp: N N N2 molecule has 2 lone pair of electrons. Lone pair of electron: A pair of electron in the valence shell that does not participate in chemical bond formation.

Question 400

38.The residual attractive or repulsive forces between molecules or atomic groups that do not arise from a covalent bond, or ionic bonds is called _____ . (A) Neutral Bond (B) Non Polar Bond (C) Electrovalent bond (D) Vanderwaals bond

Answer 400

(D) (SSC CHSL 2016) Exp: The residual attractive or repulsive forces between molecules or atomic groups that do not arise from a covalent bond or ionic bond is called vanderwaals bond. Vanderwaals forces (bond) term is used to define intermolecular forces. These are weak forces. These forces arise due to the following type of interactions:- (i) Dispersion forces or London forces. (ii) Dipole-dipole forces (iii) Dipole - induced dipole forces.

Question 401

39.Water has high boiling point because it:- (A) Is Ionic (B) Is Covalent (C) Has High Dielectric Constant (D) Is having Hydrogen Bonding

Answer 401

(D) [SSC CGL 2013] Exp: Water has high boiling point due to presence of hydrogen bonding.

Question 402

40. Which one does not contain Hydrogen bonding? (A) CH4 (B) H2O (C) NH3 (D) HCOOH

Answer 402

(A) Exp: In the given options, CH4 does not contain hydrogen bonding. Hydrogen bonding is possible when most electronegative atoms like N, O & F are present in molecule.

Question 403

40.Which of the following is the weakest bond? (A) Covalent bond (B) Ionic bond (C) Metallic bond (D) Hydrogen bond

Answer 403

(D) Exp: In the given options, Hydrogen bond is the weakest bond. The strength of hydrogen bond ranges from 10 - 40 KJmol-1

Question 404

41.Which among the following compounds has the strongest Hydrogen bond? (A) HI (B) HCl (C) HF (D) HBr

Answer 404

(C) [SSC CPO 2016] Exp: HF has strongest hydrogen bond because hydrogen bonding takes place between hydrogen and electronegative elements (F, O, N) and F is the highest electronegative atom. H H H H H F F F F F

Question 405

42.The maximum number of hydrogen bonds in a H2O molecule is- (A) 1 (B) 2 (C) 3 (D) 4

Answer 405

(D) Exp: The maximum number of Hydrogen bonds in a H2O molecule is 4. Oxygen atom of H2O molecule form two hydrogen bonds while two hydrogen atoms form two other hydrogen bonds.

Question 406

43.What are the types of bonds present in CuSO45H2O? (A) Electrovalent and Covalent (B) Electrovalent and Co-ordinate(C) Electrovalent, Covalent, Co-ordinate and Hydrogen bond (D) Covalent, Co-ordinate and Covalent

Answer 406

(C) [SSC CHSL 2015] Exp: The Cu2+ ions are attracted towards SO4 2- ions not only by ionic interactions (electrovalent) but also by coordinate covalent bonds. The Cu2+ ions form co-ordinate covalent bonds with water as well as sulphate ions. Also hydrogen bond is present in water and sulphate ion

Question 407

44.H2O is liquid and H2S is a gas because- (A) Oxygen forms stronger hydrogen bond than sulphur (B) Oxygen is less electronegative than sulphur (C) Atomic radius of oxygen is less than that of sulphur (D) Atomic radius of oxygen is greater than that of sulphur

Answer 407

(A) Exp: In water, Oxygen is highly electronegative than sulphur. As a result, hydrogen bonding is present in H2O molecule while hydrogen bonding is almost negligible in H2S. As a result, H2O exists in liquid state and H2S exists in gaseous state.

Question 408

45.The High Boiling Point of water compared to Hydrogen Sulphide or Hydrogen Chloride is due to- (A) Dipole Insulation (B) Hydrogen bonding (C) Polar covalent bonding (D) Vander wall’s attraction

Answer 408

(B) [SSC CGL 2012] Exp: Boiling Point of water is high due to Hydrogen bonding.

Question 409

46.Strenght of hydrogen bonding in O, F, S, Cl, N is in the order: (A) Cl < S < N < O < F (B) Cl < F < S < N < O (C) Cl < N < S < O < F (D) Cl < O < S < N < F

Answer 409

(A) Exp: Strength of a Hydrogen bonding, H……M increases with the increase in the electronegativity of M-atom. Out of the given atoms, Cl-does not form H-bond while the strength of H-bonding of other atoms is in the order S < N < O < F, since the electronegativity of these atoms also increases in the same order S < N < O < F 2.5 3.0 3.5 4.0

Question 410

47.Which among the following compounds has the strongest hydrogen bond? (A) HI (B) HCl (A) HF (D) HBr

Answer 410

(C)Exp: Hydrogen bond is formed when hydrogen atom is bonded to highly electron negative atoms such as as Fluorine, Oxygen or Nitrogen. Order of strength of H-bond:- H-F > H-O > H-N

Question 411

48.The hybridisation of C in CO2 is- (A) sp (B) sp2 (C) sp3 (D)None

Answer 411

(A) Exp: In CO2 molecule 2 sigma bonds are present so sp hybridisation is present in CO2 molecule. O C

Question 412

50. Hybridisation involves: (A) Separation of atomic orbitals (B) Overlapping of atomic orbitals (C) Mixing of atomic orbitals (D) All of them

Answer 412

(C) Exp: Linear mixing of atomic orbitals to form equal no. of Molecular orbitals having equal energy, is called Hybridisation & the newly formed orbitals are called as Hybrid Orbitals.

Question 413

51.What happens when one s and one p orbital is hybridized? (A) We get three orbitals in a plane (B) We get two orbitals at 180 degrees (C) We get two mutually perpendicular orbitals (D) We get four orbitals directed tetrahedrally

Answer 413

(B) (SSC CHSL 2016) Exp: Molecular orbital (MO) Theory was developed by F. Hund R.S. Mulliken in 1932. According to this theory - The number of molecular orbitals formed is equal to the number of combining orbitals. When two atomic orbitals combine, two molecular orbitals are formed.

Question 414

52.Benzene is ______ in ethyl alcohol. (A) Soluble (B) Solute (C) Insoluble (D) Insolate

Answer 414

(C) (SSC CHSL 2016) Exp: Polar molecules are soluble in polar solvents while nonpolar molecules are soluble in nonpolar solvents. Benzene is a nonpolar molecule while ethyl alcohol is polar solvent so it is insoluble in ethyl alcohol.

Question 415

53.Which of the following gases has the highest solubility in water at room temperature? (A) Nitrogen (B) Nitrous Oxide (C) Ammonia (D) Carbon dioxide

Answer 415

(C) (SSC CHSL 2016) Exp: Ammonia has the highest solubility in water at room temperature due to hydrogen bonding

Question 416

54.Which of the following is not soluble in water? (A) Lead sulphate (B) Zinc sulphate (C) Potassium sulphate(D) Sodium sulphate

Answer 416

(A) (SSC CGL 2016) Exp: In the given options, Lead Sulphate is not soluble in water. In lead sulphate, lattice energy is greater than hydration energy.

Question 417

55.Molten NaCl is good conductor of electricity because it has:- (A) Free electron (B) Free ions (C) Free molecules (D) None

Answer 417

(B) Exp: Molten NaCl is good Conductor of electricity is due to presence of free ions. However it does not conduct in solid state because of strong electrostatic forces between the ions. So, ions are not free.

Question 418

56.Which of the following bonds is the weakest in nature? (A) Single bond (B) Double bond (C) Triple bond (D) Hydrogen bond

Answer 418

(D) (SSC CGL 2017) Exp: Hydrogen bond is the weakest in nature. Hydrogen bond is formed when H atom is covalently bonded to electronegative atoms such as F, O & N.

Question 419

1. Who proposed the Modern Periodic Table? (A) Faraday (B) Mendeleev (C) Newton (D) Bohr

Answer 419

(B) (SSC CHSL 2016) Exp: Periodic table was proposed by Dimitri Mendeleev (Russian Scientist)

Question 420

2.Total number of Inner Transition Elements are- (A) 16 (B) 28 (C) 32 (D) 33

Answer 420

(B) [SSC MTS 2008] Exp: Total number of inner transition elements is 28 in which 14 elements are lanthanoides or lanthanides (58Ce - 71Lu) and other 14 are Actinoids or Actinides (90Th - 103Lr). Note: Lanthanoids are also called rare earth elements.

Question 421

3.In the periodic table, the element with atomic number 38 belongs to: (A) Period IV and group II (B) Period IV and group IV (C) Period III and group IV (D) Period V and group II

Answer 421

(D) Exp: Noble gases are 2He (1st period), 10Ne (2nd period), 18Ar (3rd period) 36Kr (4th period), 54Xe (5th period) etc. Since the atomic number of the given element is 38, this element is present in 5th period and 2nd group in the periodic table

Question 422

4.Which of the following is not a representative element? (A) Fe (B) K (C) Ba (D) N

Answer 422

(A) Exp: Representative elements are s-and p-block elements. Since K and Ba are s-block elements and N is a p-block element, these are reprsentative elements. Fe is a dblock element (transition metal).

Question 423

5.The Modern Periodic Table consists of 18 groups and 7 periods. What is the atomic number of the element placed in the 4th group and the 4th period? (A) 24 (B) 20 (C) 22 (D) 12

Answer 423

(C) (SSC CHSL 2016) Exp: 4th group of Modern Periodic Table has Titanium in 4th period (Ti = 22), Zirconium in 5th period(Zr = 40), Hafnium in 6th period (Hf = 72) and Rutherfordium in 7th period (Rf = 104).

Question 424

6.The modern periodic table consists of 18 groups and 7 periods. What is the atomic number of the element placed in the 3rd group and the 4th period? (A) 23 (B) 21 (C) 19 (D) 11

Answer 424

(B) (SSC CHSL 2016) Exp: 3rd group has 4 elements - Scandium (Sc = 21) belongs to 4th period. Yittrium (Y = 39) belongs to 5th period Lanthanum (La = 57) belongs to 6th period Actinium (Ac = 89) belongs to 7th period.

Question 425

7.The Modern Periodic table consists of 18 groups and 7 periods. What is the atomic number of the element placed in the 2nd group and the 4th period? (A) 20 (B) 22 (C) 18 (D) 10

Answer 425

(A) (SSC CHSL 2016) Exp: Calcium (Z = 20) is placed in 2nd group and 4th period. IInd group of periodic table is known as alkaline earth metals. It has 6 elements. These are- Beryllium (Be=4) - 2nd period Magnesium (Mg=12) - 3rd period Calcium (Ca=20) - 4th period Strontium (Sr=38) - 5th period Barium (Ba=56) - 6th period Radium (Ra=88) - 7th period

Question 426

8.In the Modern Periodic table one of the following does not have appropriate position: (A) Inert gases (B) Inner-transition elements (C) Transition elements (D) Fluorine

Answer 426

(B) Exp: If we look at the modern periodic table, we find that inner-transition elements have not been placed in the main body of the periodic table. These elements have been put at a separate place at the bottom of the periodic table.

Question 427

9.The Modern Periodic Table consists of 18 groups and 7 periods. What is the atomic number of the element placed in the 1st group and the 4th period? (A) 21 (B) 17 (C) 19 (D) 9

Answer 427

(C) (SSC CHSL 2016) Exp: Potassium (Z = 19) is placed in 1st group and 4th period. Ist group has 7 elements these are -Hydrogen (H=1) belongs to 1st period. Lithium (Li=3) belongs to 2nd period. Sodium (Na=11) belongs to 3rd period.Potassium (K=19) belongs to 4th period.Rubidium (Rb=37) belongs to 5th period. Cesium (Cs=55) belongs to 6th period. Francium (Fr=87) belongs to 7th period.

Question 428

10.The electronegativity of the following elements increases in the order: (A) C, N, Si, P (B) N,Si,C,P (C) Si, P, C, N (D) P, Si, N, C

Answer 428

(C) Exp: We know that in a period, Electronegativity increases and in a group electronegativity decreases. On this basis we write the following order of electronegativity values of the given elements (i) C < N (same period) (ii) Si < P (same period) (iii) C > Si (same group) (iv) N > P (same group).

Question 429

11.The correct order of electronegativity of F, N, O and P is: (A) F >N >P >O (B) F >O >P >N (C) F >O >N >P (D) N> O> F > P

Answer 429

(C) Exp: We know that in a peroid, Electronegativity increases and in a group electronegativity decreases. Thus on the basis we can write the relations: (i) N < O < F (same period) (ii) P < N (same group). On combining these relations we can write P < N < O < F or F > O > N > P.

Question 430

12. Electronegativity values of Fe, Fe2+ and Fe3+ are in the order: (A) Fe> Fe2+ >Fe3+ (B) Fe2+ >Fe > Fe3+ (C) Fe3+ > Fe> Fe2+ (D) Fe3+ > Fe2+ > Fe

Answer 430

(D) Exp: Since the size of the given species increases in the order: Fe3+ < Fe2+ < Fe, electronegativity values of these species decrease as Fe3+ > Fe2+ > Fe.

Question 431

12.Which among the following elements has highest electronegativity? (A) Gallium (B) Sodium (C) Arsenic (D) Cesium

Answer 431

(C) (SSC CHSL 2016) Exp: In the given options, Arsenic has highest electronegativity. Electronegativity generally increases on moving across a period from left to right. This is due to decrease in atomic size and increases in effective nuclear charge. Electronegativity generally decreases from top to bottom in a group a as atomic size increases and the bonding electrons become away from the nucleus.

Question 432

13.Element with Highest Ionization energy is- (A) Hydrogen (B) Helium (C) Lithium (D) Sodium

Answer 432

(B) [SSC MTS 2008] Exp: In the given options helium has highest ionization energy. This is attributed to completely filled stable configuration of Helium. 2He - 1s2 Completely filled 1s orbital

Question 433

14.Nitrogen has higher ionization energy than oxygen because in Nitrogen there is- (A) Small Atomic Radii (B) High Nuclear Charge (C) Half Filled Stable configuration in 2p orbital (D) High Bond Dissociation energy

Answer 433

(C) [SSC CHSL 2013] Exp: Nitrogen has higher ionization energy than oxygen because in Nitrogen there is half filled stable configuration in 2p orbital. 7N - 1s2, 2s22p3 8O - 1s2, 2s22p4 Note: The completely filled and completely half filled subshells are stable due to symmetrical distribution of electrons and exchange energy.

Question 434

15.Ionization Potential for inert gas is (A) Zero (B) Low (C) High (D) Negative

Answer 434

(C) [SSC CHSL 2016] Exp: The Ionization Potential for inert gas is very high. This is attributed to the completely filled stable configurations. However, the ionisation potential decreases with increase in Atomic Number from He to Rn due to increase in size.

Question 435

16.Which of the following atoms has the lowest ionisation potential? (A) N (B) Cs (C) As (D) O

Answer 435

(B) [SSC CHSL 2016] Exp: In Cesium (Cs), the outermost electron is farthest from the nucleus and so minimum energy is required to remove outermost electron from the atom. Hence Cs has lowest Ionisation Potential.

Question 436

17.Who amongst the following gave the ‘Periodic Law’? (A) Carlton McGee (B) Emil Fischer (C) Charles Darwin (D) Dmitri Mendeleev

Answer 436

(D) (SSC CPO 2017) Exp: Dmitri Mendeleev gave the ‘Periodic Law’. According to him, the physical & chemical properties of the elements are periodic function of their Atomic Mass. After Mendeleev, Mosley gave ‘Modern Periodic Law’ which states that Physical & Chemical properties of the elements are periodic function of their atomic number or no. of protons.

Question 437

18.’Rn’ is chemical symbol of which element? (A) Radium (B) Radon (C) Rhenium (D) Ruthenium

Answer 437

(B) (SSC CPO 2017) Exp: Element Symbol Radium Ra Radon Rn Rhenium Rh Ruthenium Ru

Question 438

20. What is the chemical symbol of ‘Iron’? (A) Ir (B) Fe (C) F (D) In

Answer 438

(B) (SSC CPO 2017) Exp: Chemical symbol of Iron is Fe. Atomic number is 26.

Question 439

21.In a periodic table, while moving from left to right in a period, number of _____ remains same. (A) Electrons (B) Protons (C) Shells (D) Neutrons

Answer 439

(C) (SSC CPO 2017) Exp: On moving in period from left to right, no. of shells remains same while no. of electrons, protons & neutrons changes.

Question 440

22.What is the common characteristic of the elements of the same group in the periodic table? (A) Electrons in outer most shell (B) Total number of electrons (C) Total number of protons (D) Atomic weight

Answer 440

(A) (SSC CGL 2017) Exp: The common characteristic of the elements of the same group in the periodic table is no. of electrons in outermost shell or valence shell. eg:- H 1s1 Li 1s2, 2s1 Na 1s2,2s22p6 ,3s1 K 1s2,2s2 2p6,3s2 3p6,4s1 Rb 1s2,2s2 2p6,3s2 3p6 3d10,4s2 4p6,5s1 H, Li, Na, K & Rb are elements of same group (1st group) having one valence electron.

Question 441

1.Major portion of the earth’s crust is mainly constituted by (A) Oxygen and Iron (B) Oxygen and Silicon (C) Silicon and Iron (D) Silicon and Aluminium

Answer 441

(B) (SSC CHSL 2016) Exp: Oxygen constitutes nearly half (46.6%) and silicon about one quarter (25.7%) of the total mass of the elements in the earth’s crust.

Question 442

2.The most abundant metal in the Earth’s crust is (A) Zinc (B) Copper (C) Aluminium (D) Iron

Answer 442

(C) (SSC CGL 2016) Exp: The most abundant metal in earth crust is Aluminium (8.3% by weight) while iron (4.7% by weight) is second most abundant metal

Question 443

3.The most abundant element on the earth is- (A) Calcium (B) Silicon (C) Oxygen (D) Nitrogen

Answer 443

(C) [SSC CPO 2015] Exp: Oxygen is the most abundant element on the earth crust with 46.6%.

Question 444

4.Bridgmanite is (A) A bridge on the river Thames (B) Name of a game (C) Earth’s most abundant mineral (D) Name of a music

Answer 444

(C) (SSC CGL 2016) Exp: Bridgmanite is the most abundant mineral on Earth. It makes up about 70% of the earth’s lower mantle and 38% of total volume of earth. It is made up of high density magnesium iron silicate. This name is in honour of Percy Bridgman.

Question 445

5.Which of the following metal is found in Free State? (A) Copper (B) Iron (C) Tin (D) Lead

Answer 445

(A) Exp: Copper is found in both states free and combined. It is a transition element. Early Man first of all used copper Metal.

Question 446

6.Which of the following metal is found in free state in nature? (A) Aluminium (B) Gold (C) Iron (D) Lead

Answer 446

(B) [SSC MTS 2011] Exp: Gold is found in free state in nature. Gold, Platinum are noble metals.

Question 447

7.Haematite is an ore/mineral of (A) Zinc (B) Iron (C) Lead (D) Manganese

Answer 447

(B) (SSC CHSL 2016) Exp: Haematite (Fe2O3) is main ore of iron. It is also called red oxide of iron. It contains 69.9% iron.

Question 448

8.Chromite is an ore/mineral of (A) Zinc (B) Uranium (C) Titanium (D) Chromium

Answer 448

(D) (SSC CHSL 2016) Exp: Chromite is an iron chromium oxide (FeCr2O4).

Question 449

9.Turquoise is an ore/mineral of (A) Copper (B) Manganese (C) Mercury (D) Tin

Answer 449

(A) (SSC CHSL 2016) Exp: Turquoise is a hydrated phosphate of copper and aluminium. So in the given options it is an ore/mineral of copper.

Question 450

10.Malachite is an ore/mineral of (A) Lead (B) Manganese (C) Mercury (D) Copper

Answer 450

(D) (SSC CHSL 2016) Exp: Malachite is an ore of copper. Malachite is a green copper carbonate hydroxide mineral [CuCO3.Cu (OH2)]

Question 451

11.Sphalerite is an ore/mineral of (A) Mercury (B) Molybdenum (C) Zinc (D) Silver

Answer 451

(C) (SSC CHSL 2016) Exp: Sphalerite is the major ore of Zinc. It is also known as blende or Zinc blende.

Question 452

12.Carnotite is an ore/mineral of (A) Beryllium (B) Chromium (C) Uranium (D) Copper

Answer 452

(C) (SSC CHSL 2016) Exp: Carnotite is a potassium uranium vandate with chemical formula K2(UO2) 2 (VO4) 2.3H2O. It is an ore of Uranium.

Question 453

13.Manganite is an ore/mineral of (A) Beryllium (B) Chromium (C) Manganese (D) Copper

Answer 453

(C) (SSC CHSL 2016) Exp: Manganite is a mineral of manganese. It is composed of manganese oxide hydroxide, MnO (OH). However, main ore of managanese is pyrolusite (MnO2).

Question 454

14.Cinnabar is an ore/mineral of (A) Lead (B) Manganese(C) Molybdenum (D) Mercury

Answer 454

(D) (SSC CHSL 2016) Exp: Cinnabar (HgS) is an ore of Mercury.

Question 455

15.Molybdenite is an ore/mineral of (A) Molybdenum (B) Nickel (C) Silver (D) Tin

Answer 455

(A) (SSC CHSL 2016) Exp: Molybdenite (MoS2) is a principle source of molybdenum. It is a sulphide mineral.

Question 456

16.Magnetite is an ore/mineral of (A) Beryllium (B) Chromium (C) Iron (D) Lead

Answer 456

(C) (SSC CHSL 2016) Exp: Magnetite (Fe3O4) is an ore of Iron. It is magnetic ore of iron. It contains 72.3% iron.

Question 457

17.Beryl is an ore/mineral of (A) Nickel (B) Beryllium (C) Lead (D) Tin

Answer 457

(B) (SSC CHSL 2016) Exp: Beryl (Be3Al2Si6O18) is an ore of Beryllium. Note: Phenacite is also an ore of Beryllium.

Question 458

18.The common name of Lead (II) Sulphide is (A) Borax (B) Epsom salt (C) Galena (D) Brimstone

Answer 458

(C) (SSC CHSL 2016) Exp: Borax or sodium tetraborate [Na2B4O7.10H2O] Galena or Leadsulphide [PbS] Epsom salt or Magnesium Sulphate Heptahydtrate [MgSO4.7H2O] Brimstone - It is common name of Sulphur. Galena is main ore of Lead.

Question 459

19.Pyrolusite is an ore/mineral of ___________. (A) Mercury (B) Manganese (C) Molybdenum (D) Lead

Answer 459

(B) (SSC CHSL 2016) Exp: Pyrolusite (MnO2) is an ore of Manganese.

Question 460

20.Ilmenite is an ore/mineral of _________. (A) Titanium (B) Copper (C) Lead (D) Manganese

Answer 460

(A) (SSC CHSL 2016) Exp: Ilmentite is the titanium iron oxide (FeTiO3) mineral. It is the most important ore of Titanium.

Question 461

21.Uraninite is an ore/mineral of _______. (A) Zinc (B) Uranium (C) Titanium (D) Aluminium

Answer 461

(B) (SSC CHSL 2016) Exp: Uraninite, formerly pitchblende is an ore of uranium.

Question 462

22.Aluminium is extracted from - (A) Mica (B) Copper (C) Bauxite (D) Gold

Answer 462

(C) [SSC MTS 2014] Exp: Aluminium is not found in native (free) state. It is found in combining state with different minerals. Aluminium has three principle ores Bauxite, Diaspora, cryolite. Bauxite Al2O3.2H2O, Diaspore AlO(OH), Cryolite Na3AlF6

Question 463

23.The ore of Aluminium is - (A) Fluorspar (B) Bauxite (C) Haematite (D) Chalco Pyrites

Answer 463

(B) [SSC CGL 2015] Exp: Bauxite is Al2O3.2H2O

Question 464

24. Most important ore of Lead is- (A) Galena (B) Magnetite (C) Pyrolusite (D) Siderite

Answer 464

(A) [SSC CHSL 2010] Exp: Galena (PbS) and Anglesite (PbCl2) are the ores of Lead.

Question 465

24.Magnetite is - (A) Fe2 O3 (B) Fe3O4 (C) Fe2CO3 (D) 2Fe2O3.3H2O

Answer 465

(B) [SSC CGL Exam, 2014] Exp: Magnetite is a mineral and one of the main iron ores. With the chemical formula Fe3O4, it is one of the oxides of iron.

Question 466

25.Which one of the following is an iron ore? (A) Bauxite (B) Magnetite (C) Lignite (D) Nitrite

Answer 466

(B) [SSC Steno 2011] Exp: Bauxite - Aluminium ore Lignite - A type of Coal Magnetite - Iron ore Nitrite - Ion

Question 467

26.Which one of the following Mineral does not contain Oxygen? (A) Haematite (B) Bauxite (C) Cryolite (D) Calcite

Answer 467

(C) [SSC CHSL Exam, 2014] Exp: Cryolite (Na3AlF6) mineral does not contain Oxygen. Calcite (CaCO3) contains Carbon, Oxygen and Calcium. Bauxite contains Aluminium, Oxygen. Na3AlF6 is sodium Hexa fluoro aluminates.

Question 468

27.Ruby and Sapphire are the oxides of - (A) Copper (B) Tin (C) Iron (D) Aluminium

Answer 468

(D) [SSC CGL 2008] Exp: Ruby and Sapphire are the oxides of Aluminium.

Question 469

28.Of the following commonly used materials, the one that is not an alloy is (A) Steel (B) Brass (C) Bronze (D) Copper

Answer 469

(D) (SSC CGL 2016) Exp: In the given option, Copper is metal while Steel, Brass and Bronze are alloy. Stainless steel - Fe = 73%, Cr = 18%, Ni = 8%, carbon = low amountBrass - Cu = 60%, Zn = 40% Bronze - Cu = 88%, Sn = 12%

Question 470

30. Bronze is an alloy of- (A) Copper and zinc (B) Tin and Zinc (C) Copper and Tin (D) Iron and Zinc

Answer 470

(C) (SSC CGL 2016) Exp: Bronze is an alloy of copper and tin. It consists of 88% of copper and 12% of tin. It is used in the manufacturing of doors, windows, sculptures and utensils.

Question 471

32.Which of the following does not contain silver? (A) German Silver (B) Horn Silver (C) Ruby Silver (D) Lunar Silver

Answer 471

(A) [SSC CGL 2013] Exp: German Silver contains Copper (60%), Zinc (20%) and Nickel (20%).

Question 472

33.Brass contains - (A) Copper and Zinc (B) Copper and Tin (C) Copper and silver (D) Copper and Nickel

Answer 472

(A) [SSC CGL 2014] or Brass is made of - (A) Copper and tin (B) Tin and lead (C) Copper and Zinc (D) Copper, tin and Zinc (C) [SSC CHSL 2011] Exp: Brass is a metal alloy, made up of Copper and Zinc. The proportions of zinc and copper can be varied to create a range of brass with varying properties.

Question 473

34.Which of the following metal forms Amalgam with other metals? (A) Lead (B) Zinc (C) Mercury (D) Copper

Answer 473

(C) [SSC CGL 2005] Exp: Mercury on reacting with other metals form Amalgam. For Example- Dental Amalgam (Silver-Mercury), Potassium Amalgam, Sodium Amalgam, gold Amalgam, Aluminium Amalgam etc. Mercury is used in Thermometer.

Question 474

35.Amalgam is an alloy in which the base metal is- (A) Aluminium (B) Mercury (C) Copper (D) Zinc

Answer 474

(B) [SSC Stenographer 2012] Exp: Mercury on reacting with other metals form Amalgam. For Example- Dental Amalgam (Silver-Mercury), Potassium Amalgam, Sodium Amalgam, gold Amalgam, Aluminium Amalgam etc. Mercury is used in Thermometer.

Question 475

36.German Silver contains following Metals - (A) Copper, Zinc, Nickel (B) Copper, Zinc, Silver (C) Copper, Zinc, Aluminium (D) Zinc, Silver Nickel

Answer 475

(A) [SSC LDC 2005] Or German Silver, used for making utensils is an alloy of- (A) Copper, Silver, Nickel (B) Copper, Zinc, Nickel (C) Copper, Zinc, Aluminium (D) Copper, Nickel, Aluminium (B) [SSC CPO 2007] or

Question 476

Which of the following is not contained by the German Silver? (A) Copper (B) Nickel (C) Silver (D) Zinc

Answer 476

(C) [SSC Section off. - 2007] Exp: German silver varies in composition, the percentage of the three elements ranging approximately as follows:- Copper (50% to 61.6%), Zinc (19% to 17.2%), Nickel (30% to 21.1%). The proportions are always specified in commercial alloys.