Chapter 18, Problem 6STP

Interpretation Introduction

Interpretation: Oxidizing agent in lead storage battery needs to be identified.

Concept introduction: Oxidizing agent gains one or more electrons from another reactant. Due to this reason, it gets reduced.

Answer to Problem 6STP

  ${\text{PbO}}_{\text{2}}$ is an oxidizing agent.

Explanation of Solution

B.

Overall chemical reaction that happens in lead storage automobile battery is as follows:

$\text{Pb}\left(s\right)+{\text{PbO}}_2\left(s\right)+{\text{2H}}_{\text{2}}{\text{SO}}_{\text{4}}\left(aq\right)\to 2{\text{PbSO}}_{\text{4}}\left(s\right)+2{\text{H}}_{\text{2}}\text{O}\left(l\right)$

In this reaction, oxidation state of Pb increase from 0 to +2. Thus Pb is oxidized. In case of ${\text{PbO}}_{\text{2}}$

$\left({\text{Pb}}^{\text{4+}}\right)$ , the oxidation state decrease from +2 to +4. Thus ${\text{PbO}}_{\text{2}}$ is an oxidizing agent.

Conclusion

A. Pb

Pb is not an oxidizing agent as its oxidation state increases from 0 to +2.

C. ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$

  ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ is not an oxidizing agent as no change in oxidation state of any element takes place.

D. ${\text{PbSO}}_{\text{4}}$

  ${\text{PbSO}}_{\text{4}}$ is not an oxidizing agent.