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

HCl being stronger reducing agent reduces `MnO_(4)^(-) "to" Mn^(2+)` and result of the titration becomes unsatisfactory.