Chapter 14, Problem 30E

For each reaction, indicate which elements are oxidized and which are reduced:

$\begin{array}{l}\text{a}{\text{. 2Al+3CU}}^{\text{2+}}\to {\text{2Al}}^{\text{3+}}\text{+3Cu}\\ \text{b}{\text{. 2H}}^{\text{+}}\text{+Ni}\to {\text{Ni}}^{\text{2+}}{\text{+H}}_{\text{2}}\\ \text{c}{\text{. 2I}}^{\text{-}}{\text{+Cl}}_{\text{2}}\to {\text{I}}_{\text{2}}{\text{+2Cl}}^{\text{-}}\end{array}$