Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$BaSO_3(s) + H_2SO_4(aq) \longrightarrow BaSO_4(s) + SO_2(g) + H_2O(l)$

What is a redox reaction? Explain its uses.

Identify whether the following reactions act as oxidation or reduction processes:
$(i)$ $FeSO_4 + Mg \to MgSO_4 + Fe$
$(ii)$ $Cu + 4HNO_3 \to Cu(NO_3)_2 + 2NO_2 + 2H_2O$
$(iii)$ $H_2S + Cl_2 \to S + 2HCl$

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$3AgNO_3 + Na_3PO_4 \longrightarrow Ag_3PO_4 \downarrow + 3NaNO_3$

In basic medium,$CrO_{4}^{2-}$ oxidises $S_{2}O_{3}^{2-}$ to form $SO_{4}^{2-}$ and itself changes into $Cr(OH)_{4}^{-}$. The volume of $0.154 \ M \ CrO_{4}^{2-}$ required to react with $40 \ mL$ of $0.25 \ M \ S_{2}O_{3}^{2-}$ is ........... $mL$ (Rounded-off to the nearest integer).

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