Chapter 19, Problem 19.100SP

The Nernst equation applies to both cell reactions and half reactions. For the conditions specified, calculate the potential for the following half-reactions at 25 ^oC.

1. $I_2(s)+2e^{-}\to 2I^{-}(aq);[I^{-}]=0.020\text{M}$
2. $F{e}^{3+}(aq)+e^{-}\to F{e}^{2+}(aq);[F{e}^{3+}]=[F{e}^{2+}]=0.10\text{M}$
3. $S{n}^{2+}(aq)\to S{n}^{4+}(aq)+2e^{-};[S{n}^{2+}]=1.0\times {10}^{-3}\text{M},[S{n}^{4+}]=0.40\text{M}$
4. ${\text{2Cr}}^{\text{3+}}{\text{(aq)+7H}}_{\text{2}}\text{O(l)}\to {\text{CrO}}_{\text{7}}{}^{\text{2-}}{\text{(aq)+14H}}^{\text{+}}{\text{(aq)+6e}}^{\text{-}}{\text{;[Cr}}^{\text{3+}}{\text{]=[Cr}}_{\text{2}}{\text{O}}_{\text{7}}{}^{\text{2-}}\text{]=1}{\text{.0M,[H}}^{\text{+}}\text{]=0}\text{.010M}$