Chemistry Class 11 NCERT Solutions: Chapter 8 Redox Reactions Part 8

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Chemistry Class 11 NCERT Solutions Chapter 8 Redox Reactions Part 8

Q: 13. Identify the substance oxidised, reduced, oxidising agent and reducing agent for each of the following reactions:

(A)

(B)

(C)

(D)

(E)

Answer:

(A) Oxidised substance →

Reduced substance →

Oxidising agent →

Reducing agent →

Q 13 A Structure of Silver Bromide

Q 13 a Structure of Silver Bromide

Q 13 A Structure of Silver Bromide

(B) Oxidised substance →

Reduced substance →

Oxidising agent →

Reducing agent → HCHO

(C) Oxidised substance →

Reduced substance →

Oxidising agent →

Reducing agent →

(D) Oxidised substance →

Reduced substance →

Oxidising agent →

Reducing agent →

(E) Oxidised substance →

Reduced substance →

Oxidising agent →

Reducing agent →

Q: 14. Consider the reactions:

Why does the same reductant, thiosulphate react differently with iodine and bromine?

Answer

The average oxidation number (O.N.) of S in is +2. Being a stronger oxidising agent than oxidised , in which the O.N. of S is +6. However, is a weak oxidising agent. Therefore, it oxidised in which the average O.N of S is only +2.5. As a result, reacts differently with iodine and bromine.

Q: 15. Justify giving reactions that among halogens, fluorine is the best oxidant and among

a Hydrohalic compound, hydroiodic acid is the best reductant.

Answer

as:

On the other hand, , and cannot oxidize . The oxidizing power of halogens increases in the order of . Hence, fluorine is the best oxidant among halogens.

HI and can reduce , but HCl and HF cannot. Therefore, HI and HBr are

stronger reductants than HCl and HF.

Again, I– can reduce cannot.

Hence, hydroiodic acid is the best reductant among hydrohalic compounds.

Thus, the reducing power of hydrohalic acids increases in the order of

Q: 16. Why does the following reaction occur?

What conclusion about the compound (of which is a part) can be drawn

from the reaction.

Answer:

The given reaction occurs because oxidises reduces

In this reaction, the oxidation number (O.N.) of decreases from +8 in to +6 in

and the O.N. of F increases from –1 in F– to O in .

Hence, we can conclude that is a stronger oxidising agent than

Q: 17. Consider the reactions:

(A)

(C)

(D) → No change observed.

What inference do you draw about the behaviour of and from these reactions?

Answer:

and act as oxidising agents in reactions

(A) And

(B) Respectively. In reaction

(C) oxidises to but in reaction

(D) cannot oxidise C6H5CHO.

Hence, we can say that is a stronger oxidising agent than .