Which of the following ionic or molecular species does not disproportionate in water at room temperature?

Assign $A$,$B$,$C$,$D$ from given type of reaction.
$A$ for precipitate formation reaction.
$B$ for precipitate dissolution reaction.
$C$ for precipitate exchange reaction.
$D$ for no reaction.
$P_4 + 3NaOH + 3H_2O \longrightarrow PH_3 + 3NaH_2PO_2$
Identify the correct category for the given reaction.

Which of the following reactions are disproportionation reactions?
$(a)$ $2 Cu^{+} \rightarrow Cu^{2+} + Cu^{0}$
$(b)$ $3 MnO_{4}^{2-} + 4 H^{+} \rightarrow 2 MnO_{4}^{-} + MnO_{2} + 2 H_{2}O$
$(c)$ $2 KMnO_{4} \xrightarrow{\Delta} K_{2}MnO_{4} + MnO_{2} + O_{2}$
$(d)$ $2 MnO_{4}^{-} + 3 Mn^{2+} + 2 H_{2}O \rightarrow 5 MnO_{2} + 4 H^{+}$
Select the correct option from the following:

Which of the following can act as both an oxidizing and a reducing agent?

Which anion can undergo both oxidation and reduction?

Which of the following is not a disproportionation reaction?