Comedk
Electrochemistry
COMEDK 2025 Evening Shift
Identify the two incorrect electrochemical reactions shown as taking place in the given cells at the respective electrodes.
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| Cell | Electrode | Reaction |
|---|---|---|
| Lead-Storage Cell | Cathode | $\mathrm{Pb}+2 \mathrm{SO}_4{ }^{2-}+4 \mathrm{H}^{+}+2 \mathrm{e}^{-} \rightarrow \mathrm{PbSO}_4+2 \mathrm{H}_2 \mathrm{O}+\mathrm{SO}_2$ |
| Leclanche Cell | Cathode | $\mathrm{MnO}_2+\mathrm{NH}_4^{+}+2 \mathrm{e}^{-} \rightarrow \mathrm{MnO}+\mathrm{OH}+\mathrm{NH}_3$ |
| Mercury Cell | Anode | $\mathrm{Zn} / \mathrm{Hg}+2 \mathrm{OH}^{-} \rightarrow \mathrm{ZnO}(\mathrm{s})+\mathrm{H}_2 \mathrm{O}+2 \mathrm{e}^{-}$ |
| Fuel Cell | Cathode | $\mathrm{O}_2(\mathrm{~g})+2 \mathrm{H}_2 \mathrm{O}+4 \mathrm{e}^{-} \rightarrow 4 \mathrm{OH}^{-}$ |