For a Mg | Mg2+ (aq) || Ag+ (aq) | Ag the correct Nernst Equation is :
1
\(\mathrm{E}_{\text {cell }}=\mathrm{E}_{\text {cell }}^{\mathrm{o}}-\frac{\mathrm{RT}}{2 \mathrm{~F}} \ln \frac{\left[\mathrm{Ag}^{+}\right]}{\left[\mathrm{Mg}^{2+}\right]} \)
2
\(\mathrm{E}_{\text {cell }}=\mathrm{E}_{\text {cell }}^{\mathrm{o}}+\frac{\mathrm{RT}}{2 \mathrm{F}} \ln \frac{\left[\mathrm{Ag}^{+}\right]^{2}}{\left[\mathrm{Mg}^{2+}\right]} \)
3
\(\mathrm{E}_{\text {cell }}=\mathrm{E}_{\text {cell }}^{\mathrm{o}}-\frac{\mathrm{RT}}{2 \mathrm{F}} \ln \frac{\left[\mathrm{Mg}^{2+}\right]}{\left[\mathrm{Ag}^{+}\right]} \)
4
\(\mathrm{E}_{\text {cell }}=\mathrm{E}_{\text {cell }}^{\mathrm{o}}-\frac{\mathrm{RT}}{2 \mathrm{F}} \ln \frac{\left[\mathrm{Ag}^{+}\right]^{2}}{\left[\mathrm{Mg}^{2+}\right]}\)