Assign $A, B, C, D$ from the given type of reaction.
$H_3PO_3 \xrightarrow{\Delta} H_3PO_4 + PH_3 \uparrow$

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 best describes the behavior of bromine in the reaction given below?
$H_2O + Br_2 \to HOBr + HBr$

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

Assign $A, B, C, D$ from the given type of reaction.
$K_2MnO_4 + H^{+} \longrightarrow KMnO_4 + MnO_2 \downarrow$

Which of the following chemical substances undergoes self-oxidation and self-reduction during the same reaction?