When `KMnO_(4)` solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because -

Options

A. `CO_(2)` is formed as the product
B. reaction is exothermic
C. `MnO_(4)^(-)` catalyses the reaction
D. `Mn^(2+)` acts as autocatalyst

Answer

D

Explanation

Oxalic acid reduces `KMnO_(4)` to form `Mn^(2+)` ion, which acts as autocatalyst. `2MnO_(4)^(-)+5C_(2)O_(4)^(2-)+16H^(+)rarr 2Mn^(2+)+10CO_(2)+8H_(2)O`