A reaction, $$\mathrm{Ni}_{(\mathrm{s})}+\mathrm{Cu}_{(\mathrm{(M)})}^{+} \rightarrow \mathrm{Ni}_{(\mathrm{IM})}^{+}+\mathrm{Cu}_{(\mathrm{s})}$$ occurs in a cell. Calculate $$\mathrm{E}_{\text {cell }}^{\circ}$$ if $$\mathrm{E}_{\mathrm{Cu}}^{\circ}=0.337 \mathrm{~V}$$ and $$\mathrm{E}_{\mathrm{Ni}}^{\circ}=-0.257 \mathrm{~V}$$

Calculate $$\Delta \mathrm{G}^{\circ}$$ for the cell:

$$\mathrm{Sn}_{(\mathrm{s})}\left|\mathrm{Sn}_{(\mathrm{1M})}^{2+}\right|\left|\mathrm{Ag}_{(\mathrm{1M})}^{+}\right| \mathrm{Ag}_{(\mathrm{s})}$$ at $$25^{\circ} \mathrm{C}\left(\mathrm{E}_{\text {cell }}^{\circ}=0.90 \mathrm{~V}\right)$$

Calculate current in ampere required to deposit $$4.8 \mathrm{~g} ~\mathrm{Cu}$$ from it's salt solution in 30 minutes. [Molar mass of $$\mathrm{Cu}=63.5 \mathrm{~g} \mathrm{~mol}^{-1}$$ ]

Identify the gas produced due to reduction of $$\mathrm{NH}_4^{+}$$ ions at cathode during working of dry cell.