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A lead storage battery is discharged. During the charging of this battery, the reaction that occurs at anode, is
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Verified Answer
The correct answer is:
$\mathrm{PbSO}_4(\mathrm{~s})+2 \mathrm{H}_2 \mathrm{O}(\mathrm{I}) \longrightarrow$
$\mathrm{PbO}_2(\mathrm{~s})+\mathrm{SO}_4^{2-}(\mathrm{aq})+4 \mathrm{H}^{+}(\mathrm{aq})+2 \mathrm{e}^{-}$
$\mathrm{PbO}_2(\mathrm{~s})+\mathrm{SO}_4^{2-}(\mathrm{aq})+4 \mathrm{H}^{+}(\mathrm{aq})+2 \mathrm{e}^{-}$
During recharging, the cell is operated like an electrolytic cell. The electrode reactions are the reverse of those that occur during discharge.
At cathod
$$
\mathrm{PbSO}_4(s)+2 e^{-} \longrightarrow \mathrm{Pb}(s)+\mathrm{SO}_4^{2-}(\mathrm{aq})
$$
At anode $\mathrm{PbSO}_4(s)+2 \mathrm{H}_2 \mathrm{O}(l) \longrightarrow$
$$
\mathrm{PbO}_2(s)+\mathrm{SO}_4^{2-}(\mathrm{aq})+4 \mathrm{H}^{+}(\mathrm{aq})+2 e^{-}
$$
Net reaction
$$
\begin{aligned}
& 2 \mathrm{PbSO}_4(s)+2 \mathrm{H}_2 \mathrm{O}(l) \longrightarrow \\
& \mathrm{Pb}(s)+\mathrm{PbO}_2(s)+4 \mathrm{H}^{+}(\mathrm{aq})+2 \mathrm{SO}_4^{2-}(\mathrm{aq})
\end{aligned}
$$
At cathod
$$
\mathrm{PbSO}_4(s)+2 e^{-} \longrightarrow \mathrm{Pb}(s)+\mathrm{SO}_4^{2-}(\mathrm{aq})
$$
At anode $\mathrm{PbSO}_4(s)+2 \mathrm{H}_2 \mathrm{O}(l) \longrightarrow$
$$
\mathrm{PbO}_2(s)+\mathrm{SO}_4^{2-}(\mathrm{aq})+4 \mathrm{H}^{+}(\mathrm{aq})+2 e^{-}
$$
Net reaction
$$
\begin{aligned}
& 2 \mathrm{PbSO}_4(s)+2 \mathrm{H}_2 \mathrm{O}(l) \longrightarrow \\
& \mathrm{Pb}(s)+\mathrm{PbO}_2(s)+4 \mathrm{H}^{+}(\mathrm{aq})+2 \mathrm{SO}_4^{2-}(\mathrm{aq})
\end{aligned}
$$
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