In which reaction does an element undergo the greatest change in oxidation number?
- A$\text{Cr}_2\text{O}_7^{2-} + 6\text{Fe}^{2+} + 14\text{H}^+ \rightarrow 2\text{Cr}^{3+} + 6\text{Fe}^{3+} + 7\text{H}_2\text{O}$
- B$3\text{OCl}^- \rightarrow \text{ClO}_3^- + 2\text{Cl}^-$
- C$5\text{Fe}^{2+} + \text{MnO}_4^- + 8\text{H}^+ \rightarrow 5\text{Fe}^{3+} + \text{Mn}^{2+} + 4\text{H}_2\text{O}$
- D$\text{PbO}_2 + \text{Sn}^{2+} + 4\text{H}^+ \rightarrow \text{Sn}^{4+} + \text{Pb}^{2+} + 2\text{H}_2\text{O}$