When $KMnO_4$ reacts with acidified $FeSO_4$,which of the following occurs?

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$FeCl_3 + Na_3PO_4 \longrightarrow FePO_4 \downarrow + 3NaCl$

How many moles of acidic $KMnO_4$ are required to oxidize $1$ mole of ferrous oxalate $(FeC_2O_4)$?

$I^{-}(aq.) + MnO_4^{-}(aq.) \xrightarrow{H^{+}} X + Mn^{2+}(aq.)$
$I^{-}(aq.) + MnO_4^{-}(aq.) \xrightarrow{\text{Neutral or weakly } OH^{-}} Y + MnO_2$
$MnO_4^{-}(aq.) + Mn^{2+}(aq.) \xrightarrow{ZnSO_4} Z + 4H^{+}$
Products $X, Y$ and $Z$ are respectively :

Match the following columns:-

Column-$I$ [Type of reaction]	Column-$II$ [Example]
$I$. Intermolecular redox reaction	$A$. $CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O$
$II$. Intramolecular redox reaction	$B$. $NH_4NO_2 \rightarrow N_2 + 2H_2O$
$III$. Disproportionation reaction	$C$. $2H_2O_2 \rightarrow 2H_2O + O_2$
$IV$. Comproportionation reaction	$D$. $KClO_3 \rightarrow KCl + \frac{3}{2}O_2$

When $SO_2$ gas is passed through an acidified solution of $K_2Cr_2O_7$,the solution turns........