Question

Amount of oxalic acid present in a solution can be determined by its titration with $KMn{O}_4$ solution in the presence of $H_{2}S{O}_4$. The titration gives an unsatisfactory result when carried out in the presence of $HCl$ because $HCl$:

• A. reduces permanganate to $M{n}^{2+}$
• B. oxidises oxalic acid to carbon dioxide and water
• C. gets oxidised by oxalic acid to chlorine
• D. omits $H^{+}$ ions in addition to those from oxalic acid

Answer 1

The correct option is A reduces permanganate to $M{n}^{2+}$

Option (A) is correct.
The titration gives unsatisfactory result when carried out in the presence of $HCl$, because $HCl$ reduces permanganate to $M{n}^{2+}$.
$KMn{O}_4$ can oxidise $HCl$ (along with $H_2{C}_2{O}_4$) into ${Cl}_2$ and itself gets reduced to $M{n}^{2+}$.
Hence, the titration should be carried out in presence of sulphuric acid.