When an oxide of

A=MnO₂, B=K₂MnO₄, C= KMnO₄, D= KIO₃

When Manganese dioxide(A) is fused with KOH, it gives a green solution of potassium manganate(B).

2MnO₂ (A) + 4KOH +O₂→ 2K₂MnO₄(B) +2H₂O

Potassium manganate disproportionates to give purple potassium permanganate(C).

3MnO₄^2- +H⁺→2MnO₄^-(C)+MnO₂ +2H₂O

Potassium permanganate on reacting with KI gives potassium iodate(D) and manganese dioxide again

2MnO₄^- +H₂O +KI → 2MnO₂ + 2OH^- + KIO₃(D)