$3ClO^- \to ClO_3^- + 2Cl^-$; This reaction is an example of which of the following?

Refer to the periodic table and answer the following questions:
$(a)$ Select the possible non-metals that can show disproportionation reactions.
$(b)$ Select three metals that can show disproportionation reactions.

Which of the following substances acts as both an oxidizing agent and a reducing agent?

$1 \text{ mole}$ of $MnO_4^{2-}$ disproportionates into $MnO_4^-$ and $MnO_2$ in an acidic medium. Calculate the percentage by mass of $Mn$ converted to $MnO_4^-$ (Molar mass of $Mn = 55 \ g/mol$).

In the reaction $P_4 + 3KOH + 3H_2O \to PH_3 + 3KH_2PO_2$,phosphorus is .........

$3 ClO_{3}^{-}(aq) \rightarrow ClO^{-}(aq) + 2 ClO_{3}^{-}(aq)$ is an example of