Which of the following statements regarding the preparation of potassium permanganate is correct?

Solution

1. The industrial preparation involves fusing ${\text{MnO}}_2$ with $\text{KOH}$ in the presence of air to form green ${\text{K}}_2{\text{MnO}}_4$.
2. The green manganate ion (${\text{MnO}}_4^{2-}$) is stable only in alkaline medium.
3. In acidic medium, the manganate ion undergoes disproportionation to form purple permanganate (${\text{MnO}}_4^{-}$) and ${\text{MnO}}_2$.
4. Potassium permanganate is a very strong oxidizing agent, not a weak one.
5. Hence the answer is (A).