When solid potassium halides are treated with concentrated sulfuric acid, the equations below are given: Equation 1: $2\text{KCl} + \text{H}_2\text{SO}_4 \rightarrow \text{K}_2\text{SO}_4 + 2\text{HCl}$ Equation 2: $2\text{KBr} + 2\text{H}_2\text{SO}_4 \rightarrow \text{K}_2\text{SO}_4 + \text{SO}_2 + \text{Br}_2 + 2\text{H}_2\text{O}$ Equation 3: $8\text{KI} + 5\text{H}_2\text{SO}_4 \rightarrow 4\text{K}_2\text{SO}_4 + \text{H}_2\text{S} + 4\text{I}_2 + 4\text{H}_2\text{O}$ What is the greatest change in sulfur’s oxidation number in each reaction?
Chemistry 9701 · AS & A Level · Electrochemistry