JEE Main 2025 — Electrochemistry Question with Solution

$\begin{array}{lll}\text{ Cathode }& (\mathrm{Ag}+(\mathrm{aq})+{\mathrm{e}}^{-}& \to \mathrm{Ag})\times 2\\ \text{ Anode }& \mathrm{Mg}& \to {\mathrm{Mg}}^{2+}(\mathrm{aq})+2{\mathrm{e}}^{-}\end{array}$
By Nernst equation $\begin{aligned} & \mathrm{E}_{\text {cell }}=\mathrm{E}_{\mathrm{cell}}^{\circ}-\frac{\mathrm{RT}}{\mathrm{nF}} \ln \mathrm{Q} \\ & \mathrm{E}_{\text {cell }}=\mathrm{E}_{\mathrm{cell}}^{\circ}-\frac{\mathrm{RT}}{\mathrm{nF}} \ln \frac{\left[\mathrm{Mg}^{2+}\right]}{\left[\mathrm{Ag}^{+}\right]^2} \\ & =\mathrm{E}_{\text {cell }}^{\circ}+\frac{\mathrm{RT}}{2 \mathrm{~F}} \ln \frac{\left[\mathrm{Ag}^{+}\right]^2}{\left[\mathrm{Mg}^{2+}\right]} \end{aligned}$