Question

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

Answer 1

Correct Answer: 8

To solve this problem, we need to determine the number of moles of \(H^+\) ions required for the reaction where \(MnO_4^-\) oxidizes oxalate ions \((C_2O_4^{2-})\) to carbon dioxide \((CO_2)\). The balanced redox reaction in an acidic medium is:

\(2MnO_4^- + 5C_2O_4^{2-} + 16H^+ \rightarrow 2Mn^{2+} + 10CO_2 + 8H_2O\)

Let's break down the stoichiometric coefficients:

1. 1 mole of \(MnO_4^-\) reacts with 5/2 = 2.5 moles of \(C_2O_4^{2-}\).
2. For every 2 moles of \(MnO_4^-\), 16 moles of \(H^+\) are needed. Therefore, for 1 mole of \(MnO_4^-\), 16/2 = 8 moles of \(H^+\) are required.

Hence, the number of moles of \(H^+\) ions required by 1 mole of \(MnO_4^-\) is 8.

This result is verified as falling within the provided range of 8 to 8.

Answer 2

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 \(\text{MnO}_4^-\).