$2 \text{ mol}$ of $FeSO_4$ are oxidized by $X \text{ mol}$ of $KMnO_4$ whereas $2 \text{ mol}$ of $FeC_2O_4$ are oxidized by $Y \text{ mol}$ of $KMnO_4$. The ratio of $X$ and $Y$ is:

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$Na_3PO_4 + Fe_2(SO_4)_3 \longrightarrow FePO_4 \downarrow + Na_2SO_4$

The treatment of an aqueous solution of $3.74 \ g$ of $Cu(NO_3)_2$ with excess $KI$ results in a brown solution along with the formation of a precipitate. Passing $H_2S$ through this brown solution gives another precipitate $X$. The amount of $X$ (in $g$) is. . . . . [Given : Atomic mass of $H=1, N=14, O=16, S=32, K=39, Cu=63, I=127$ ]

One litre of $0.15 \ M \ Na_2SO_3$ aqueous solution is mixed with $500 \ mL$ of $0.2 \ M \ K_2Cr_2O_7$ aqueous solution in acid medium. What is the concentration (in $mol \ L^{-1}$) of unreacted $K_2Cr_2O_7$ in the resultant solution?

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$Cu^{2+} (aq.) + 2I^{-} \longrightarrow CuI \downarrow + \frac{1}{2}I_2$

Match the reactions in Column $I$ with the nature of the reactions/type of the products in Column $II$.

Column $I$	Column $II$
$A$. $O_2^{-} \rightarrow O_2 + O_2^{2-}$	$p$. redox reaction
$B$. $CrO_4^{2-} + H^{+} \rightarrow$	$q$. one of the products has trigonal planar structure
$C$. $MnO_4^{-} + NO_2^{-} + H^{+} \rightarrow$	$r$. dimeric bridged tetrahedral metal ion
$D$. $NO_3^{-} + H_2SO_4 + Fe^{2+} \rightarrow$	$s$. disproportionation