Chapter 14, Problem 35QP

In the following oxidation-reduction reactions, identify the oxidizing agent, the reducing agent, and the number of electrons transferred.

$\begin{array}{l}\left(\text{a}\right){\text{ I}}_{\text{2}}\left(aq\right)+{\text{2OH}}^{-}\left(aq\right)\to {\text{I}}^{-}\left(aq\right)+{\text{IO}}^{-}\left(aq\right)+{\text{H}}_{\text{2}}\text{O}\left(l\right)\hfill \\ \left(\text{b}\right)\text{ Cr}\left(s\right)+{\text{2H}}^{\text{+}}\left(aq\right)\to {\text{Cr}}^{\text{2+}}\left(aq\right)+{\text{H}}_{\text{2}}\left(g\right)\hfill \\ \left(\text{c}\right){\text{ 2Cr}}_{\text{2}}{\text{O}}_7^{2-}\left(aq\right)+{\text{16H}}^{+}\left(aq\right)\to {\text{4Cr}}^{\text{3+}}\left(aq\right)+{\text{3O}}_{\text{2}}\left(g\right)+{\text{8H}}_{\text{2}}\text{O}\left(l\right)\hfill \\ \left(\text{d}\right){\text{ 3Fe}}^{\text{3+}}\left(aq\right)+\text{Al}\left(s\right)\to {\text{3Fe}}^{2+}\left(aq\right)+{\text{A1}}^{\text{3+}}\left(aq\right)\hfill \end{array}$