$Zn^{2+}_{(aq)} + 2e^- \to Zn_{(s)}$. This is

What is a redox couple?

In the following reaction,$3CuO + 2NH_3 \to N_2 + 3H_2O + 3Cu$,what happens during the conversion of $NH_3$ to $N_2$?

In the reaction,$SO_2 + 2H_2S \longrightarrow 3S + 2H_2O$,the substance that is oxidised is

In the reaction,$2KMnO_4 + 16HCl \rightarrow 5Cl_2 + 2MnCl_2 + 2KCl + 8H_2O$,the reduction product is

Observe the following reactions:
$I$. $2H_2O_{(l)} + 2Na_{(s)} \rightarrow 2NaOH_{(aq)} + H_{2(g)}$
$II$. $2H_2O_{(l)} + 2F_{2(g)} \rightarrow 4H^{+}_{(aq)} + 4F^{-}_{(aq)} + O_{2(g)}$
Identify the correct statement from the following: