Chapter 17, Problem 34P

A galvanic cell is constructed in which the overall reactionis
${\text{Cr}}_{\text{2}}{\text{O}}_7^{2-}\left(aq\right)+14{\text{H}}_{\text{2}}{\text{O}}^{+}\left(aq\right)+6{\text{I}}^{-}\left(aq\right)\to 2{\text{Cr}}^{3+}\left(aq\right)+3{\text{I}}_2\left(s\right)+21{\text{H}}_{\text{2}}\text{O}\left(\mathcal{l}\right)$

1. Calculate $\Delta E°$ for this cell.
2. At pH 0, with $\left[{\text{Cr}}_{\text{2}}{\text{O}}_7^{2-}\right]=1.5\text{M}$ and $\left[{\text{I}}^{-}\right]=0.40\text{M,}$ the cell potential is found to equal 0.87 V. Calculatethe concentration of ${\text{Cr}}^{3+}\left(aq\right)$ in the cell.