Which one of the following reactions is not feasible?

Which of the following reduction products of $NO_3^-$ involves the maximum number of moles of electrons taken up per mole of $NO_3^-$?

In which of the following conversions does a blue colour appear?

Match the chemical reactions given in List-$I$ with their types given in List-$II$:

List-$I$	List-$II$
$A$. $TiCl_{4(l)} + 2Mg_{(s)} \xrightarrow{\Delta} Ti_{(s)} + 2MgCl_{2(s)}$	$I$. Disproportionation reaction
$B$. $2H_2O_{2(aq)} \rightarrow 2H_2O_{(l)} + O_{2(g)}$	$II$. Metal displacement reaction
$C$. $C_{(s)} + O_{2(g)} \xrightarrow{\Delta} CO_{2(g)}$	$III$. Decomposition reaction
$D$. $2NaH_{(s)} \xrightarrow{\Delta} 2Na_{(s)} + H_{2(g)}$	$IV$. Combination reaction

$A$ 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. . . . .

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$Pb(NO_3)_2 + H_2SO_4 \longrightarrow PbSO_4 \downarrow + 2HNO_3$