Question

An example for autocatalysis is

• A. oxidation of $NO$ to $NO_2$
• B. oxidation of $SO_2$ to $SO_3$
• C. decomposition of $KClO_3$ to $KCl$ and $O_2$
• D. oxidation of oxalic acid by acidified $KMnO_4$

Answer 1

Answer: (D)

oxidation of oxalic acid by acidified $KMnO_4$

Answer 2

Autocatalysis is a process in which one of the product behaves as a catalyst.

e.g. ,$2KMnO_4 + 5H_2C_2O_4 + 3H_2SO_4 \to$
$K_2SO_4 + \underset{\text{(acts as catalyst)}}{{2MnSO_4}} +8H_2O + 10CO_2$

The pink colour of $KMnO_4$disappears slowly on reaction with oxalic acid, but the rate of disappearance of colour fastens after some time due to the formation of $MnSO_4$ which acts as auto catalyst for the reaction.