Amount of oxalic acid present in a solution can be determined by its titration with `KMnO_(4)` solution in the presence of `H_(2)SO_(4)`. The titration gives unsatisfactory result when carried out in the presence of `HCl`, because `HCl`:

Explanation

Titration of oxalic acid by `KMnO_(4)` in the presence of HCl gives unsatisfactory result because HCl also reduces `MnO_(4)^(-) "to" Mn^(2+)`