Chapter 3, Problem 149QRT

(a)

Interpretation Introduction

Interpretation:

The oxidation number for chlorine atom in the given molecules ${\text{Cl}}_{\text{2}}{\text{, HOCl, ClO}}_{\text{2}}{\text{, NH}}_{\text{4}}\text{Cl, and NaCl}$ has to be assigned.

Concept introduction:

Oxidation number:

The oxidation number of an element is zero. The oxidation number of a monoatomic ion equals its charge.

The oxidation number is zero for the summation of the oxidation numbers complete atoms in a complete formula.

The charge on the ion is equal to the summation of the oxidation numbers of complete atoms in poly atomic ion.

The oxidation state of alkali metal $(\text{Li, Na, K, Rb, Cs})$ is $+1$, and alkaline earth metal is $\text{(Be, Mg, Ca, Sr, Ba)}$ is $+2$.

The oxidation state of hydrogen is $+1$ (without bonding with metals), the oxidation state of oxygen is $-2$.

(b)

Interpretation Introduction

Interpretation:

Whether the given ${\text{Cl}}_{\text{2}}{\text{, HOCl, ClO}}_{\text{2}}{\text{, NH}}_{\text{4}}\text{Cl, and NaCl}$ compounds are oxidizing agent or reducing agent has to be identified and decreasing order of their oxidizing strengths has been ranked.

Concept introduction:

An oxidizing agent gains the electrons and is reduced in a chemical reaction and it is electron acceptor.

A reducing agent loses electrons and is oxidized in a chemical reaction and it is electron donor.  The oxidation state is called as oxidation number, which describes degree of oxidation (loss of electrons) of an atom in a chemical compound. Theoretically, the oxidation state is positive, negative or zero.