A solution contains Fe^2+, Fe^3+ and I^- ions. This solution was treated with iodine at 35°C. E^° for Fe^3+ / Fe^2+ is +0.77 V and E^° for I_2 / 2…

A solution contains $\displaystyle \mathrm{Fe}^{2+}, \mathrm{Fe}^{3+}$ and $\displaystyle \mathrm{I}^{-}$ ions. This solution was treated with iodine at $\displaystyle 35$°C. $\displaystyle \mathrm{E}^{\circ}$ for $\displaystyle \mathrm{Fe}^{3+} / \mathrm{Fe}^{2+}$ is +$\displaystyle 0.77$ V and $\displaystyle \mathrm{E}^{\circ}$ for $\displaystyle \mathrm{I}_2 / 2 \mathrm{I}^{-}=0.536 \mathrm{~V}$. The favourable redox reaction is :