Chapter 19, Problem 28QP

Write the Nernst equation for the following processes at some temperature T:

$\begin{array}{l}\left(\text{a}\right)\hfill \\ \text{Mg}\left(s\right){\text{ + Sn}}^{\text{2+}}\left(aq\right)\underset{}{\rightleftarrows }{\text{ Mg}}^{\text{2+}}\left(aq\right)\text{ + Sn}\left(s\right)\hfill \\ \text{(b)}\hfill \\ \text{2Cr}\left(s\right){\text{ + 3Pb}}^{\text{2+}}\left(aq\right)\underset{}{\rightleftarrows }{\text{2Cr}}^{\text{3+}}\text{(}aq\text{)+3Pb}\left(s\right)\hfill \end{array}$