Amount of oxalic acid present in a solution can be determined by its titration with KMnO4 solution in the presence of H2SO4. The titration gives unsatisfactory result when carried out in the presence of HCl, because HCl
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gets oxidised by oxalic acid to chlorine
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furnishes H+ions in addition to those from oxalic acid
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reduces permanganate to Mn2+
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oxidises oxalic acid to carbon dioxide and water
