In the reaction of gold with aqua regia,the oxidation state of Nitrogen changes from

Assign $A, B, C, D$ from the given type of reaction.
$ZnSO_4 \, (aq) + MgCl_2 \, (aq) \longrightarrow$ No reaction

$CO_2$ and $SO_2$ gases can be distinguished by using:

$A$ sample $(5.6 \ g)$ containing iron is completely dissolved in cold dilute $HCl$ to prepare $250 \ mL$ of solution. Titration of $25.0 \ mL$ of this solution requires $12.5 \ mL$ of $0.03 \ M \ KMnO_4$ solution to reach the end point. The number of moles of $Fe^{2+}$ present in the $250 \ mL$ solution is $x \times 10^{-2}$ (consider complete dissolution of $FeCl_2$). The amount of iron present in the sample is $y \%$ by weight. (Assume: $KMnO_4$ reacts only with $Fe^{2+}$ in the solution. Use: Molar mass of iron as $56 \ g \ mol^{-1}$)
$(1)$ The value of $x$ is. . . . .
$(2)$ The value of $y$ is. . . . .

In order to oxidize a mixture of one mole of each of $FeC_2O_4$,$Fe_2(C_2O_4)_3$,$FeSO_4$ and $Fe_2(SO_4)_3$ in acidic medium,the number of moles of $KMnO_4$ required is

Match the following types of reactions in List-$I$ with their corresponding unbalanced equations in List-$II$.

List-$I$ (Type of reaction)	List-$II$ (Unbalanced equation)
$A$. Combination reaction	$(i)$ $AgNO_3 + CaCl_2 \longrightarrow AgCl + Ca(NO_3)_2$
$B$. Decomposition reaction	$(ii)$ $Cl_2 \longrightarrow Cl^- + ClO_3^-$
$C$. Disproportionation reaction	$(iii)$ $Mg + N_2 \longrightarrow Mg_3N_2$
$D$. Displacement reaction	$(iv)$ $KClO_3 \xrightarrow{\Delta} KCl + O_2$