Chapter 14, Problem 46QP

Balance the following half-reactions.

$\begin{array}{l}\left(\text{a}\right)\text{ Ni}\left(s\right)\to {\text{Ni}}^{2+}\left(aq\right)\hfill \\ \left(\text{b}\right){\text{ Br}}_{\text{2}}\left(g\right)\to {\text{Br}}^{-}\left(aq\right)\hfill \\ \left(\text{c}\right){\text{ Mg}}^{2+}\left(aq\right)\to \text{Mg}\left(s\right)\hfill \\ \left(\text{d}\right){\text{ Cr}}^{3+}\left(aq\right)\to {\text{Cr}}^{2+}\left(aq\right)\hfill \end{array}$