Chapter 20, Problem 45A

Interpretation Introduction

Interpretation:

In lead acid battery, which substance is to be reduced, which substance is to be oxidized and which substance is to be produced in each reaction needs to be determined.

Concept introduction:

A lead storage battery is a type of rechargeable battery. These batteries have moderate power density and good response time. These batteries are affected by temperature.

Answer to Problem 45A

Lead dioxide is reduced ${\text{PbO}}_{\text{2}}$

Lead electrode is oxidized ${\text{Pb}}^{\text{+2}}$

${\text{2PbSO}}_{\text{4}}$ andlead dioxide is produced during the charging and discharging of the battery.

Explanation of Solution

In lead acid battery, the negative terminal composed of ${\text{Pb}}^{\text{+2}}$ ion and the positive electrode composed of ${\text{PbO}}_{\text{2}}$.

Reaction at cathode

${\text{Pb}}^{\text{+2}}{\text{ + SO}}_{\text{4}}{}^{\text{2-}}\to {\text{PbSO}}_{\text{4}}{\text{+ 2e}}^{\text{-}}$

Lead electrode is oxidized to supply electron.

Reaction at anode

$\begin{array}{l}{\text{PbO}}_{\text{2}}{\text{ + H}}_{\text{2}}{\text{SO}}_{\text{4}}\text{ + e }\to \text{ PbSO4}\hfill \\ \hfill \end{array}$

Lead dioxide electrode was reduced by addition of electrons.

During charging of s battery, the combine reaction of reaction at cathode and at anode is

${\text{2PbSO}}_{\text{4}}{\text{+ 2H}}_{\text{2}}\text{O }\Rightarrow {\text{ PbO}}_{\text{2}}{\text{+ Pb + 2H}}_{\text{2}}{\text{SO}}_{\text{4}}$

Lead dioxide is produced during the charging.

During discharging of a battery, the combine reaction of reaction at cathode and anode is

${\text{PbO}}_{\text{2}}{\text{+ Pb + 2H}}_{\text{2}}{\text{SO}}_{\text{4}}\Rightarrow {\text{ 2PbSO}}_{\text{4}}{\text{+ 2H}}_{\text{2}}\text{O}$

Lead sulphate ${\text{2PbSO}}_{\text{4}}$ and water are produced during the discharging

Conclusion

Lead dioxide is reduced ${\text{PbO}}_{\text{2}}$

Lead electrode is oxidized ${\text{Pb}}^{\text{+2}}$

${\text{2PbSO}}_{\text{4}}$ andlead dioxide is produced during the charging and discharging of the battery.