Oxidation and reduction

Question 1

All redox reactions are:

Answer 1

exothermic

Question 2

can fluorine give a disproportionate reaction?

Answer 2

No
because it is the strongest oxidizing element

Question 3

mnemonic for oxidation and reduction is ;)

Answer 3

LEOGER

Question 4

electrolysis is a redox reaction in which

Answer 4

oxidation takes place at anode
reduction takes place at cathode

Question 5

lewis acids are

Answer 5

oxidants

Question 6

lewis bases are

Answer 6

reductants

Question 7

reduction property …………. down the group

Answer 7

increases

Question 8

oxidation property …………. down the group

Answer 8

decreases

Question 9

starch iodine paper is used for

Answer 9

test the presence of an oxidizing agent
where starch is the one who works

Question 10

the oxidation state of +8 is shown by

Answer 10

Ruthenium and osmium

Question 11

The oxidation number is zero in

Answer 11

1. allotropes
2. alloys
3. metals of metal carbonyls
4. free state
5. amalgam

Question 12

The bleaching action of chlorine is

Answer 12

oxidation and is permanent

Question 13

bleaching action of SO2 is

Answer 13

reduction and temporary

Question 14

Oxidation number of Mg in chlorophyll is

Answer 14

+2

Question 15

Oxidation number of iron in haemoglobin is

Answer 15

+2

Question 16

The oxidation number of iron in methemoglobin is

Answer 16

+3

Question 17

increase in O.N makes the radii

Answer 17

decrease

Question 18

decrease in O.N makes the radii

Answer 18

increase its size

Question 19

O.N of basic compounds is

Answer 19

less than oxidation number of amphoteric compounds which is inturn less than the oxidation number of acidic compounds

Question 20

the thermal stability of oxyacids:

Answer 20

increases with the increase in oxidation number

Question 21

the oxidation number of hydrogen is +1 in all cases except in :

Answer 21

metal hydrides that has -1 oxidation state

Question 22

non-metals that are reducing agents:

Answer 22

carbon, sulphur, hydrogen

Question 23

Schweitzer reagent is used for the manufacturing of artificial silk. its molecular formula is

Answer 23

[Cu(NH3)4] SO4
also known as tetramine copper sulphate

Question 24

the strongest reducing agent is

Answer 24

lithium in solution and cesium in air

Question 25

the strongest oxidizing agent is

Answer 25

Flourine

Question 26

compounds that act as reducing as well as oxidizing agents are

Answer 26

H2SO3
HNO2
SO2
H2O2

Question 27

increase in O.N means:

Answer 27

increase in acidity

Question 28

The highest electrical conductivity of the following aqueous solutions is of

(1) 1 M acetic acid

(2) 1 M chloroacetic acid

(3) 1 M fluoroacetic acid

(4) 1 M difluoroacetic acid

Answer 28

More the acidity more will be the tendency to release protons. So lighter will be the electrical conductivity. Difluoroacetic acid will be the strongest acid because of the electron-withdrawing effect of two fluorine atoms so it will show maximum electrical conductivity.

Hence option (4) is the answer.

Question 29

Amount of oxalic acid present in a solution can be determined by its titration with KMnO4 solution in the presence of H2SO4. The titration gives unsatisfactory result when carried out in the presence of HCl because HCl

(1) gets oxidised by oxalic acid to chlorine

(2) furnishes H+ ions in addition to those from oxalic acid

(3) reduces permanganate to Mn2+

(4) Oxidises oxalic acid to carbon dioxide and water

Answer 29

HCl is a strong reducing agent. It reduces permanganate to Mn2+.

Hence option (3) is the answer.