How many electrons $(e^-)$ are gained by the oxidizing agent $KMnO_4$ to convert into $MnO_4^{2-}$,$MnO_2$,$Mn_2O_3$,and $Mn^{2+}$ respectively?

The product $D$ in the following reaction sequence is:

For the reaction $SO_2 + 2H_2S \to 3S + 2H_2O$,which option represents twice the equivalent weight of the oxidizing agent?

Assign $A, B, C, D$ from the given type of reaction.
$Ba(NO_3)_2 + Na_2SO_4 \longrightarrow BaSO_4 \downarrow + 2NaNO_3$

Assign $A, B, C, D$ from the given type of reaction:
$2FeCl_3 + 3KI \longrightarrow 2FeCl_2 + I_2 + 2KCl$
$I_2 + KI \longrightarrow KI_3$
Identify the observation for the product $KI_3$ in the reaction $FeCl_3 + KI \longrightarrow Fe^{2+}(aq.) + KI_3$.

Assign $A, B, C, D$ from the given type of reaction: $2NaNO_3 + H_2SO_4(conc.) \xrightarrow{Hot} Na_2SO_4 + 2NO_2 + \frac{1}{2}O_2 + H_2O$. (Note: The reaction is a thermal decomposition redox reaction).