Ncert Exercises & Solutions

Identify the correct statement (s) in relation to the following reaction.

$Zn + 2 HCl \to {ZnCl}_{2} + H_{2}$

1. Zinc is acting as an oxidant

2. Chlorine is acting as a reductant

3. Hydrogen ion is acting as an oxidant

4. Zinc is acting as a reductant

(c, d)

Writing the oxidation number of each element above its symbol, so that

\overset{0}{Zn} + 2 \overset{+ 1}{H} \overset{- 1}{Cl} \to \overset{+ 2}{Zn} {\overset{- 1}{Cl}}_{2} + {\overset{0}{H}}_{2}

(a) The oxidation number of Zn increases from 0 in Zn to +2 in ZnCl₂, therefor, Zn acts as a reductant. Thus, option (a) is incorrect.

(b) The oxidation number of chlorine does not change, therefore, it neither acts as a reductant nor an oxidant. Therefore, option (b) is incorrect.

(c) The oxidation number of hydrogen decreases from +1 in H⁺ to 0 in H₂, therefore, H⁺ acts as an oxidant. Thus, option (c) is correct.

(d) As explained in option (a), Zn acts as reductant, therefore, it cannot act as an oxidant. Thus, option (d) is correct.