Question

The oxidizing agent in the lead storage battery is

• A. $Pb$
• B. ${PbO}_2$
• C. ${PbSO}_4$
• D. $H_2{SO}_4$

Answer 1

The correct option is B

${\mathrm{PbO}}_2$

Explanation for the correct option:

(B):

• The substances which have the ability to oxidize others and get reduced by themselves are known as oxidizing agents. Whereas the substances which have the ability to reduce others and get oxidized by themselves are known as reducing agents.
• Lead ($\mathrm{Pb}$) storage battery, also known as a Lead-acid battery, is the earliest known form of rechargeable battery. Lead storage batteries are energy storing devices.
• The reaction of the Lead storage battery is:
  $$\begin{gathered} \mathrm{Pb}\left(\mathrm{s}\right)+{\mathrm{PbO}}_2\left(\mathrm{s}\right)+2{\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)\to 2{\mathrm{PbSO}}_4\left(\mathrm{aq}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right) \\ \mathrm{Lead}\mathrm{Lead}\left(\mathrm{IV}\right)\mathrm{Sulfuric}\mathrm{Lead}\mathrm{Water} \\ \mathrm{oxide}\mathrm{acid}\mathrm{sulfate} \end{gathered}$$
• Since the oxidation state of $\mathrm{Pb}$ changes from +4 in ${\mathrm{PbO}}_2$ to +2 in ${\mathrm{PbSO}}_4$, thus it is getting reduced. Hence, it acts as an oxidizing agent.

Explanation for the incorrect options:

(A) The oxidation state of Lead changes from zero in $\mathrm{Pb}$ to +2 in ${\mathrm{PbSO}}_4$, thus it is getting oxidized. Hence, it is the reducing agent.

(C) ${\mathrm{PbSO}}_4$ is the product formed in the reaction. Hence, it is not an oxidizing agent.

(D) The oxidation states of Hydrogen ($\mathrm{H}$), Oxygen ($\mathrm{O}$), and Sulfur ($\mathrm{S}$) remain the same on the reactant and product side. Hence, ${\mathrm{H}}_2{\mathrm{SO}}_4$ is not an oxidizing agent.

Final Answer:

Hence, the correct option is (B).