Textbook Problem

A disproportionation reaction involves a substance that acts as both an oxidizing and a reducing agent, producing higher and lower oxidation states of the same element in the products. Which of the following disproportionation reactions are spontaneous under standard conditions? Calculate ΔG° and K at 25°C for those reactions that are spontaneous under standard conditions.

a. $2{\text{Cu}}^{+}(aq)\to {\text{Cu}}^{2+}(aq)+\text{Cu}(s)$

b. $3{\text{Fe}}^{2+}(aq)\to 2{\text{Fe}}^{3+}(aq)+\text{Fe}(s)$

c. ${\text{HClO}}_2(aq)\to {\text{ClO}}_3{}^{-}(aq)+\text{HClO}(aq)$ (unbalanced)

Use the half-reactions: