Organic Compounds Flashcards
- Why are aryl halides less reactive towards nucleophilic substitution reactions as compared to alkyl halides?
a) The formation of a less stable carbanion
b) Longer carbon halogen bond
c) The inductive effect
d) Sp2-hybridized carbon attached to the halogen
d) Sp2-hybridized carbon attached to the halogen
- Which types of isomers are formed in rearrangement reactions?
a) structural isomers
b) Geometrical isomers
c) Optical isomer
d) Conformational isomers
a) structural isomers
- What is the main difference between Hofmann and
Curtius rearrangement?
a) Products are different
b) Intermediate formed is different
c) Reactants are different
d) Isomers
c) Reactants are different
- With accompanying 1, 2-rearrangement in wolff
rearrangement, an α-diazocarbonyl compound is
converted into a ketene by loss of which of the following
compound?
a) Dioxygen
b) Dinitrogen
c) Disulphur
d) Ammonia
b) Dinitrogen
- Which intermediate carbocation is more stable in
pinacole -pinacolone rearrangement?
a) 1o
b) 2o
c) 3o
d) 4o
c) 3o
- Which Intermediate is formed in Wolff’s reaction?
a) Carbene
b) Ketene
c) Carbocation
d) Carbanion
b) Ketene
- In which medium Favorskii rearrangement occurs?
a) Acidic
b) Basic
c) Neutral
d) Alkaline
b) Basic
- What is the correct order of reactivity series of the
halogen?
a) F > Cl > Br > I
b) I > Cl > Br > F
c) F > Br > Cl > I
d) I > Br > Cl > F
a) F > Cl > Br > I
- A layer of reddish brown precipitate which is formed on the iron knife, when an iron knife is dipped in an aqueous solution of copper sulphate is of which compound or element?
a) Iron sulphate
b) Copper
c) Rust
d) Copper sulphate
b) Copper
- Which type of catalytic reaction, does Dienone phenol rearrangement reaction belong?
a) Acid catalysed
b) Base catalysed
c) Acidic
d) Neutral
a) Acid catalysed
- Which of the following statement is false for
substitution reaction?
a) One functional group in a compound replaces another functional group
b) We can classify substitution reaction by nucleophile and electrophile
c) We can classify substitution reaction only by nucleophile and electrophile
d) Substitution reactions are divided into three general
classes, depending on the type of atom or group that acts as the substituent
c) We can classify substitution reaction only by nucleophile and electrophile
- Which medium is used in benzylic acid rearrangement reaction?
a) Neutral
b) Strong basic
c) Mild acidic
d) Strong acidic
b) Strong basic
- Why the chloroform layer becomes purple, when a
colourless solution of potassium iodide is passed through a colourless solution of chloroform?
a) Iodine
b) Chlorine
c) Potassium chloride
d) Potassium iodide
View Answer
a) Iodine
- Which of the following is a not method of electron
movement?
a) Bond breaking
b) Bond making
c) Bond movement
d) Revolution of bond
d) Revolution of bond
- Which of the following statement is false for electron movement?
a) The formal charge becomes one unit more positive at the starting atom and one unit more negative at the
terminal atom
b) The last arrow in a chain must be either a bond making arrow terminating at a sextet atom, or a bond breaking arrow.
c) When a bond is broken, this is represented by a curved arrow pointing towards from the bond from which electron will be transfered and ending the arrow pointing away towards the next unoccupied molecular orbital
d) Curly arrows are superimposed over the structural
formulae of reactants in a chemical equation to show the reaction mechanism
d) Curly arrows are superimposed over the structural
formulae of reactants in a chemical equation to show the reaction mechanism
- Who proposed arrow pushing method of showing
progression of electons?
a) Sir Robert Robinson
b) Robert Burns Woodward
c) Adolf Von Baeyer
d) Victor Grignard
a) Sir Robert Robinson
- Benzyl chloride is reacted with different nucleophiles (HO–, CH3COO–, PhO–, CH3O–).
Arrange them in the decreasing order of reactivity with Benzyl chloride.
a) CH3O– > HO– > PhO– > CH3COO–
b) HO– > CH3O– > PhO– > CH3COO–
c) HO– > PhO– > CH3O– > CH3COO–
d) CH3COO– > CH3O– > HO– > PhO–
b) HO– > CH3O– > PhO– > CH3COO–
- Electrons movement take place from __________
a) positively to negatively components
b) negatively to positively charged components
c) neutral to charged species
d) charged species to neutral
b) negatively to positively charged components
- Which species are formed due to Homolytic bond
breakage?
a) Anion
b) Cation
c) Free radical
d) Atoms
c) Free radical
- Which of the following type of reaction shows
heterolytic bond cleavage?
a) SN1 reaction
b) Addition reaction
c) Elimination reaction
d) Free radical halogenation
d) Free radical halogenation
- Which of the following statement is incorrect about
nucleophiles?
a) Nucleophiles have an unshared electron pair and canmake use of this to react with an electron deficient species
b) The nucleophilicity of an element (an electron donor) generally increases on going down a group in the periodic table
c) A nucleophile is electron-deficient species
d) All good nucleophiles are good bases when we deal
across the period
c) A nucleophile is electron-deficient species
- What is the correct order of nucleophilicity in the
following options?
a) (CH3)3CO– > CH3–
b) CH3S– > CH3SH
c) CH3CH2CH2O– < (CH3)3CO–
d) (CH3CH2)3N > (CH3CH2)3P
b) CH3S– > CH3SH
- Nitro group is meta-directing in electrophilic aromatic substitution reactions?
a) increases electron density at meta-position
b) increases electrons density at ortho and para-positions
c) decreases electron density at meta-position
d) decreases electron density at ortho and para-positions
d) decreases electron density at ortho and para-positions
- The relative rates of nucleophilic substitution for the given substrates are as follows:
Compound Approx. Relative rate
CH3CH2Br 1.0
CH3CH2CH2Br 0.28
(CH3)2CHCH2Br 0.030
(CH3)3 CCH2Br 0.00000042
Which of the following statement is correct?
a) Each of the above reactions is likely to be SN2
b) Each of the above reactions is likely to be SN1
c) First two reactions follow SN2 and next two reactions follow SN1 pathway
d) There is no role of “steric factor”
a) Each of the above reactions is likely to be SN2
- Which of the following order is incorrect for the rate of E2 reaction?
a) 5-Bromocycloheptene > 4-Bromocycloheptene
b) 2-Bromo- I -phenylbutane > 3-Bromo- I-phenylbutane
c) 3-Bromocyclohexene > Bromocyclohexane
d) 3-Bromo-2-methylpentane > 2-Bromo-4-methylpentane
a) 5-Bromocycloheptene > 4-Bromocycloheptene
- Which of the following statement is correct?
a) E2 is a concerted reaction in which bonds break and
new bonds form at the same time in a single step
b) Order of reactivity of alkyl halides towards E2
dehydrohalogenation is found to be 3o > 2o > 1o
c) In E2 elimination different stereoisomer (diastereomer) converts into different stereo product
d) All of the mentioned
d) All of the mentioned
- Which of the following organic compound with
molecular formula C3H C12 exhibits only one signal in the IH NMR spectrum?
a) 2, 2-dichloropropane
b) 1, 2-dichloropropane
c) 1, 3-dichloropropane
d) 1, 1-dichloropropane
a) 2, 2-dichloropropane
- The 1H NMR spectrum of CH3OCHCICH2Cl will exhibit ________
a) A three proton doublet. One proton singlet and a two proton doublet
b) A three proton singlet. One proton singlet and a two
proton doublet
c) A three proton singlet. One proton triplet and a two
proton doublet
d) A three proton triplet. One proton triplet and a two
proton triplet
c) A three proton singlet. One proton triplet and a two
proton double
- Which of the following 1H-NMR spectrum of compound with molecular formula C4H9NO2 shows delta 5.30 (broad, IH), 4.10(q, 2H), 2.80 (d, 3H), 1.20 (t, 3H) ppm?
a) CH3NHCOOCH2CH3
b) CH3CH2NHCOOCH3
c) CH3OCH2CONHCH3
d) CH3CH2OCH2CONH2
a) CH3NHCOOCH2CH3
- Which of the compound show only one signal is present in the PMR spectra ?
a) C3H4, C3H6
b) C4H6, C5H12
a) CH3–CH2–O–CH2–CH3
c) C8H18, C2H6O
d) All of the mentioned
d) All of the mentioned
- Which of the following has three types of hydrogens in the following compounds?
a) Br-CH = CH2
b) CH3 – CH2 – CH3
c) C6H5CH2
d) CH3– CH2 – CH(CH3) – N02
a) Br-CH = CH2
- How many Hertz does 1 ppm correspond to for an PMR spectrometer operating at a radio frequency of 60 MHz and 100 MHz?
a) 6 Hz, 10 Hz
b) 60 Hz, 100 Hz
c) 100 Hz, 60 Hz
d) 10Hz, 100Hz
b) 60 Hz, 100 Hz
- What is the value of gyramagnetic ratio of proton?
a) 41.10 radian/Tesla
b) 42.57 MHz/Tesla
c) 26.75 radian/Tesla
d) 41.10 MHz/Tesla
b) 42.57 MHz/Tesla
- The distance between the centers of the peaks of
doublet is called as?
a) Coupling constant
b) Spin constant
c) Spin-spin coupling
d) Chemical shift
a) Coupling constant
- Compound C4H10O gave PMR spectrum consisting of two groups of lines (multiplets) with relative intensities in the ratio 3 : 2. Other compound of the same formula exhibited two lines with relative area of 9 : 1. What are these compounds.
a) Diethyl ether and n-butanol
b) t-Butyl alcohol and 1-Methoxypropane
c) diethyl ether and t-Butyl alcohol
d) Diethyl ether and 2-Methoxypropane
c) diethyl ether and t-Butyl alcohol
- H2, CH4, C2H6 and C6H6 exhibit which PMR spectra?
a) Singlet
b) Doublet
c) Triplet
d) Quintet
a) Singlet
- A proton Hb is coupled to four equivalent protons Ha. The multiplicity and the relative intensity of lines in the signal Hb is
a) Doublet, I : 4
b) Triplet, I : 4 : 6
c) Quintet, 1 : 4 : 6 : 4 : 1
d) Quartet, 1 : 4 : 6 : 4
c) Quintet, 1 : 4 : 6 : 4 : 1
- The 1H NMR spectrum of a dilute solution of a mixture of acetone and dichloromethane in CDCl3 exhibits two singlets of 1:1 intensity. What will be the molar ratio of acetone to dichloromethane in the solution?
a) 3:1
b) 1:3
c) 1:1
d) 1:2
b) 1:3
- In NMR spectroscopy, what is the product of Nuclear ‘g’ factor (gN), the nuclear magneton and the magnetic field strength (Bo)?
a) energy of transition from alpha to beta state
b) chemical shift
c) spin-spin coupling constant
d) magnetogyric ratio
a) energy of transition from alpha to beta state
- How many peaks are expected in low-resolution NMR spectrum of vinyl chloride and ethyl cyclopropane?
a) 3,5
b) 5,3
c) 6,3
d) 3,6
a) 3,5
- Which of the following statement is false for mass
spectroscopy?
a) Mass spectroscopy is used to identify unknown
compounds within a sample, and to elucidate the
structure and chemical properties of different molecules
b) Particle are characterized by their mass to charge ratios (m/z) and relative abundances
c) This technique basically studies the effect of ionizing
energy on molecules
d) This technique can be used on all state of matter
d) This technique can be used on all state of matter
- An organic compound (MF; C8H10O) exhibited the
following 1H NMR special data:
62.5 (3H, s), 3.8 (314, s), 6.8 (2H, d, J 8 Hz), 7.2 (2H, d, J 8 Hz) ppm. What will be the compound among the choices?
a) 4-ethylphenol
b) 2-ethylphenol
c) 4-methylanisole
d) 4-methylbenzyl alcohol
c) 4-methylanisole
- What will be the NMR frequency in MHz of bare 1H in a magnetic field of intensity 1.4092 tesla (given gN = 5.585 and μN = 5.05 x 10-27 JT-1)?
a) 60 MHz
b) 120 MHz
c) 100 MHz
d) 15 MHz
a) 60 MHz
- In which state of matter mass spectroscopy is being
performed?
a) solid
b) liquid
c) gaseous
d) plasma
c) gaseous
- At room temperature, what is the number of singlet
resonances observed in the 1H NMR spectrum of
Me3CC(O)NMe2 (N, N-Dimethylpivalamide)?
a) 3
b) 4
c) 5
d) 2
a) 3
- Which of the following main component of mass
spectroscopy deal with resolving the ions into their
characteristics mass components according to their massto-charge ratio?
a) Ion Source
b) Analyzer
c) Detector System
d) Analyzer tube
a) Ion Source
- Which species of the following is used to bombard with the sample for which mass spectroscopy has been performed?
a) Alpha particles
b) Neutrons
c) Electrons
d) Protons
c) Electrons
- Who discovered the mass spectrometer?
a) Francis Aston
b) J. J Thomson
c) Ernest O. Lawrence
d) Walter Kaufmann
b) J. J Thomson
- A PMR spectrometer operates at 300 MHz. Find the
value of magnetic field.
Given: gN = 5.585 and BN = 5.05 x 10-27 JT-I.
a) 7.05 T
b) 6.38 T
c) 7.58 T
d) 5.93 T
a) 7.05 T
- Separation of ions in mass spectrometer take place on the basis of which of the following?
a) Mass
b) Charge
c) Molecular weight
d) Mass to charge ratio
d) Mass to charge ratio
- What are the main criteria on which mass spectrometer used for?
a) Composition in sample
b) Relative mass of atoms
c) Concentration of elements in the sample
d) Properties of sample
b) Relative mass of atoms
- Which of the following comparison is correct for solvent shift on the n –>π* transition of acetone?
a) H20 = CH30H = C2H50H = CHC13 = C6H14
b) H20 > CH30H > C2H50H > CHC13 > C6H14
c) H20 < CH30H < C2H50H < CHC13 < C6H14
d) H20 > CH30H < C2H50H < CHC13 < C6H14
c) H20 < CH30H < C2H50H < CHC13 < C6H14
- What is the correct order of λmax for n –> ς* transition?
a) R-OH > R-NH2 > R-SH
b) R-OH < R-NH2 < R-SH
c) R-OH > R-SH > R-NH2
d) R-OH < R-SH < R-NH2
b) R-OH < R-NH2 < R-SH
- What is the wavelength range for UV spectrum of light?
a) 400 nm – 700 nm
b) 700 nm to 1 mm
c) 0.01 nm to 10 nm
d) 10 nm to 400 nm
a) 400 nm – 700 nm
- Which type of ionic species are allowed to pass
through the slit and reach the collecting plate?
a) Negative ions of all masses
b) positive ions of the specific mass
c) Negative ions of the specific mass
d) Positive ions of all masses
b) positive ions of the specific mass
- What is the correct order of λmax for n–> π* transition for the following three compounds?
a) RCOOH > RCOOR’ > RCONH2
b) RCOOH = RCOOR’ = RCONH2
c) RCOOH = RCOOR’ < RCONH2
d) RCOOH = RCOOR’ > RCONH2
b) RCOOH = RCOOR’ = RCONH2
- For HCI, = 1.63 x 10-27 kg, the observed frequency =
2890 or v = 8.67 x 1013 Hz. What is the force constant K?
a) 4.83 m dyn Å^-1
b) 8.43 dynes cm^-1
c) 483 μm^-1
d) 4.83 dyn Å^-1
a) 4.83 m dyn Å^-1
- The ultraviolet spectrum of benzonitrile shows a
secondary absorption band at 271 nm. If a solution of
benzonitrile in water, with a concentration of 1×10-4 molar solution is examined at 271 nm, what will be the
absorbance reading (ℇ = 1000) and what will be the
intensity ratio, IO/I, respectively?
a) 0.1, 1.26
b) 0.2, 2.26
c) 0.3, 3.26
d) 0.4, 4.26
a) 0.1, 1.26
- What is the correct order of λmax for n –> π* transition for the R-CN, R-NO2, and R-N=N-R?
a) R-CN < R-NO2 < R-N=N-R
b) R-CN = R-NO2 = R-N=N-R
c) R-CN > R-NO2 > R-N=N-R
d) R-CN > R-NO2 < R-N=N-R
a) R-CN < R-NO2 < R-N=N-R
- What is the correct order of λmax for π –> π* transition for the following three compounds?
a) R-C=C-R > R2C = CR2 > R-CHO
b) R-C=C-R < R2C = CR2 < R-CHO
c) R-C=C-R = R2C = CR2 = R-CHO
d) R-C=C-R < R2C = CR2 >R-CHO
b) R-C=C-R < R2C = CR2 < R-CHO
- The ultraviolet spectrum of benzonitrile shows a
primary absorption band at 224 nm. If a solution of
benzonitrile in water, with a concentration of 1x 10-4molar, is examined at a wavelength of 224 nm, the absorbance is determined to be 1.30. The cell length is 1 cm. What is the molar absorptivity of this absorption band?
a) 2.3 x 104
b) 3.3 x 104
c) 1.3 x 104
d) 4.3 x 104
c) 1.3 x 104
- What is the relation between restoring force, f to the
displacement q in Hooke’s law?
a) f = -kq
b) f = kq
c) f = kq^2
d) f = -kq^2
a) f = -kq
- In which unit Force constant is not expressed?
a) Dynes cm^-1
b) dyne Å^-1
c) Nm^-1
d) kp
a) 4.83 m dyn Å^-1
- The intensity of an absorption band is always
proportional to which of the following factor?
a) Atomic population
b) Molecular population of the initial state
c) Molecular population of the final state
d) Temperature
b) Molecular population of the initial state
- On which factors the vibrational stretching frequency of diatomic molecule depend?
a) Force constant
b) Atomic population
c) Temperature
d) Magnetic field
a) Force constant
- Since the nuclei in a polyatomic molecule do not always vibrate in a simple harmonic manner, there arises which of the following situation?
a) Harmonicity
b) Anharmonicity in molecular vibrations
c) Fundamental frequencies
d) Infrared
a) Harmonicity
- The vibrations, without a center of symmetry are active in which of the following region?
a) Infrared but inactive in Raman
b) Raman but inactive in IR
c) Raman and IR
d) Inactive in both Raman and IR
c) Raman and IR
- What is the correct increasing order of stretching
frequencies for C ≡ C, C = C and C — C?
a) C — C > C = C > C ≡ C
b) C ≡ C > C = C > C — C
c) C — C > C = C < C ≡ C
d) C ≡ C < C — C > C = C
b) C ≡ C > C = C > C — C
- The frequency of vibration of a bond is a function of
which factor?
a) Force constant of the bond
b) Masses of the atoms involved in bonding
c) Force constant of the bond and Masses of the atoms
d) Bond order
c) Force constant of the bond and Masses of the atoms
- What is the order of decreasing vibrational frequency for
C — Cl, C — Br, C — C, C — O and C — H?
a) C-H, C-C, C-O, C- Cl, C-Br
b) C- Cl, C-Br, C-C, C -H, C-O
c) C-O, C-H, C-Br, C- Cl, C-C
d) C-Br, C- Cl, C-C, C-O, C-H
a) C-H, C-C, C-O, C- Cl, C-Br
- Why in the IR spectrum of Benzoyl chloride, a weak
band near 1750 cm-1 is formed?
a) Inductive effect
b) Fermi resonance between C = O band and first overtone
c) Conjugation effect
d) Hyperconjugation effect
b) Fermi resonance between C = O band and first overtone
- Why ketenes absorb in IR at a very high frequency (2150 cm-1)?
a) The inner C is sp hybridized
b) The more s character in a bond, the stronger it is
c) Inner C is sp2 hybridized
d) Inner C is sp3 hybridized
c) Inner C is sp2 hybridized
- What is the effect of ring strain in lactone (cyclic ester) or a lactam (cyclic amide)?
a) Increases carbonyl stretching frequency
b) Decreases carbonyl stretching frequency
c) Increases C = C frequency
d) Decreases C = C frequency
a) Increases carbonyl stretching frequency
- Which of the following molecules will not show infrared spectrum?
a) H2
b) HCI
c) CH4
d) H20
a) H2
- What is the relation between wave number of IR
absorption and the reduced mass?
a) Wave number is directly proportional to reduced mass
b) Wave number is inversely proportional to reduced mass
c) Wave number is independent of the reduced mass
d) Wave number is directly proportional to square of
reduced mass
b) Wave number is inversely proportional to reduced mass
- Which compound having molecular formula C5H10shows absorption at 1380 cm-1?
a) 2-Methyl-1-butene
b) Cyclopentane
c) Pentyne
d) Methylcyclobutane
b) Cyclopentane
- What is the number of vibrational degrees of freedom in C6H5CH3?
a) 39
b) 15
c) 18
d) 40
a) 39
- A compound C8 H6 decolorizes Br2 in CCl4 and gives a white precipitate with Tollen’s reagent. It has sharp band at 3300 cm-l and weak bands at 3085, 2110 cm-l. What is this compound?
a) Phenyl acetylene
b) Phenyl propylene
c) Phenyl ethylene
a) Phenyl acetylene
- The phosphorescence spectrum of the excited species is due to which transition?
a) Singlet to triplet transitions
b) Triplet to singlet transitions
c) Vibration modes
d) Electron spin transitions
b) Triplet to singlet transition
- Why Monomeric saturated aliphatic carboxylic acids show carbonyl stretching frequency near 1760 cm-1, while saturated aliphatic ketones near 1720 cm-1?
a) Mesomeric (M) effect is dominant in acids over the
inductive (I) effect
b) I effect is dominant in carboxylic acids over the
mesomeric effect
c) I effect on ketones is dominant over the M effect
d) M effect in ketones is dominant
b) I effect is dominant in carboxylic acids over the
mesomeric effec
- KMnO4 reacts with oxalic acid according to the equation given below. Here 20 mL of 0.1 M KMnO4 is equivalent to how many mL and molarity of H2C2O4?
2MnO4– + 5C2O4– + 16H+ → 2Mn+1 + 10CO2 + 8H2O
a) 20 mL of 0.5 M H2C2O4
b) 50 mL of 0.5 M H2C2O4
c) 50 mL of 0.1 M H2C2O4
d) 20 mL of 0.1 M H2C2O4
c) 50 mL of 0.1 M H2C2O4
- Excess of KI reacts with CuSO4 solution and then
Na2S2O3 solution is added to it. Which of the statement is incorrect for this reaction?
a) Na2S2O3 is oxidized
b) CuI2 is formed
c) Cu2I2 is formed
d) Evolved I2 is reduced
b) CuI2 is formed
- How many moles of KMnO4 are required for complete oxidation of 1.25 mol Cu2S?
Cu2S → Cu+2 + SO2
a) 1 mole
b) 3 moles
c) 2 moles
d) 5 moles
c) 2 moles
- What is the concentration of H2O2 solution of 20 ml of H2O2 solution which will react completely with 10 ml of 2 M KMnO4 in acidic medium?
a) 1.25 M
b) 5 M
c) 2.5 M
d) 25 M
c) 2.5 M
- How many number of moles of KMnO4 will react with 180 gm H2C2O4 according to given reaction?
KMnO4 + H2C2O4 → 2C02 + Mn2+
a) 4/5
b) 2/5
c) 1/5
d) 4/3
b) 2/5
- What is the volume of 0.05 M KMnO4 which will react with 50 ml of 0.1 M H2S in acidic medium (H2S → S02)?
a) 60 ml
b) 6 ml
c) 12 ml
d) 120 ml
d) 120 ml
- How many moles of KCI are required to produce 10 mol Cl2 by the reaction with KCIO3?
a) 1.66 mole
b) 13.33 mole
c) 0.66 mole
d) 16.66 mole
d) 16.66 mole
- What is the mass of Fe304 if it reacts completely with 25 ml of 0.3m K2Cr2O7?
a) 1 .44 g
b) 10.44 g
c) 104.4 g
d) 14.4 g
b) 10.44 g
- What is the mass of K2Cr2O7 required to produce 254 gm I2 from KI solution? Given: K2Cr2O7 + 2KI → 2Cr3+ + I2
a) 49 g
b) 98 g
c) 9.8 g
d) 4.9 g
a) 49 g
- What is the volume strength of H2O2 of its 11.2 ml
requires 30 ml of 0.5 M K2Cr2O7?
a) 35
b) 55
c) 25
d) 45
d) 45