Which of the following compound undergoes disproportionation in presence of `SO_(3)` gas?

Options

A. `K_(2)MnO_(4)`
B. `K_(2)CrO_(4)`
C. `I_(2)`
D. `Mg(NO_(3))_(2)`

Answer

A

Explanation

The green solution of `MnO_(4)^(2-)(aq.)` is stable only in strong basic medium, in neutral (or) acidic (or) less basic medium it disproportionates into `MnO_2` and `MnO_(4)^(-)`.
`K_(2)MnO_(4)("green")underset(SO_(3)//"acidic medium")overset("In presence of")toKMnO_(4)("purple")+MnO_(2)("Dark brown")`