Strong reducing and oxidizing agents among the following,respectively,are

$KMnO_4$ is the oxo-salt of the acid of which of the following oxides?

When an oxide of manganese $(A)$ is fused with $KOH$ in the presence of an oxidising agent and dissolved in water,it gives a dark green solution of compound $(B)$. Compound $(B)$ disproportionates in neutral or acidic solution to give purple compound $(C)$. An alkaline solution of compound $(C)$ oxidises potassium iodide solution to a compound $(D)$ and compound $(A)$ is also formed. Identify compounds $A$ to $D$ and also explain the reactions involved.

When $MnO_2$ is fused with solid $KOH$ in the presence of air,what is the product formed and its color?

$Cu^{2+}$ aqueous solution has . . . . . . colour.

Which of the following statements is incorrect?