Match List-$I$ with List-$II$ and select the correct answer.

List-$I$	List-$II$
$1.$ Aniline	$a.$ Used in the preparation of azo dyes
$2.$ Nitrobenzene	$b.$ Sulpha drug
$3.$ Sulphanilamide	$c.$ Solvent in Friedel-Crafts reaction
$4.$ Trinitrotoluene	$d.$ Used as an explosive

Alkyl halide on heating with alc. $NH_3$ in a sealed tube results in...

Which set of products will be obtained in the following reactions?
$RCN \xrightarrow{\text{reduction}} (a)$
$RCN \xrightarrow[(ii) H_2O]{(i) CH_3MgBr} (b)$
$RNC \xrightarrow{\text{hydrolysis}} (c)$
$RNH_2 \xrightarrow{HNO_2} (d)$

Consider the above sequence of reactions. The number of bromine atom$(s)$ in the final product $(P)$ will be:

$A$ hydrocarbon $'A'$ $(C_4H_8)$ on reaction with $HCl$ gives a compound $'B'$ $(C_4H_9Cl)$,which on reaction with $1 \ mol$ of $NH_3$ gives compound $'C'$ $(C_4H_{11}N)$. On reacting with $NaNO_2$ and $HCl$ followed by treatment with water,compound $'C'$ yields an optically active alcohol,$'D'$. Ozonolysis of $'A'$ gives $2 \ mols$ of acetaldehyde. Identify compounds $'A'$ to $'D'$. Explain the reactions involved.

What does the molecular formula $C_3H_9N$ represent?