Question

Number of moles of $H^+$ ions required by 1 mole of $MnO_4^-$ to oxidise oxalate ion to $CO_2$ is ____.

Answer 1

The balanced reaction is:

$2 \text{MnO}_4^- + 5 \text{C}_2\text{O}_4^{2-} + 16 \text{H}^+ \rightarrow 2 \text{Mn}^{2+} + 10 \text{CO}_2 + 8 \text{H}_2\text{O}$

From the stoichiometry, we see that 16 moles of $\text{H}^+$ are required for 2 moles of $\text{MnO}_4^-$. Therefore, 8 moles of $\text{H}^+$ are needed for each mole of $\text{MnO}_4^-$.