In the titration of oxalic acid with acidified KMnO4 at about 60 degC, the first few drops decolourise slowly but later drops decolourise rapidly. This is because

the product Mn^2+ acts as an autocatalyst

CO2 evolved catalyses the reaction

H2SO4 becomes more concentrated as the titration proceeds

the product Mn^2+ acts as an autocatalyst

KMnO4 decomposes on standing in the burette

JEE Main levelSingle correct optionDifficulty 2 of 3df096

In the titration of oxalic acid with acidified $KMnO X_{4}$ at about $60^{\circ} C$ , the first few drops decolourise slowly but later drops decolourise rapidly. This is because

The reaction

2 MnO X_{4} X^{-} + 5 C X_{2} O X_{4} X^{2 -} + 16 H X^{+} \to 2 Mn X^{2 +} + 10 CO X_{2} + 8 H X_{2} O

is slow at first. The

Mn X^{2 +}

formed catalyses it, so the rate rises after the first few drops.