The conversion of $2,3-$dibromobutane to $2-$butene in the presence of $Zn$ is an example of ...........

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	$D$. $KClO_3 \rightarrow KCl + \frac{3}{2}O_2$

Which of the following reactants can be reduced by $SO_2$ in the given reactions?
$(I)$ $O_3 \to$ product
$(II)$ $Cr_2O_7^{2-} \xrightarrow{H^{+}} $ product
$(III)$ $MnO_4^{-} \xrightarrow{H^{+}} $ product
$(IV)$ $H_2S \to$ product

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

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$Pb(CH_3COO)_2 + Na_2CrO_4 \longrightarrow PbCrO_4 \downarrow + 2CH_3COONa$

The gaseous product of the reaction between $Sn$ and conc. $H_2SO_4$ is