Chapter 13, Problem 13.81QP

The reaction ${\text{S}}_2{\text{O}}_8^{2-}+2{\text{I}}^{-}\stackrel{}{\to }2{\text{SO}}_4^{2-}+{\text{I}}^2$ proceeds slowly in aqueous solution, but it can be catalyzed by the Fe³⁺ ion. Given that Fe³⁺ can oxidize I⁻ and Fe²⁺ can reduce, write a plausible two-step mechanism for this reaction. Explain why the uncatalyzed reaction is slow.