$A$ 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.

$A$ trinitro compound,$1,3,5$-tris-($4$-nitrophenyl)benzene,on complete reaction with an excess of $Sn/HCl$ gives a major product,which on treatment with an excess of $NaNO_2/HCl$ at $0^{\circ} C$ provides $P$ as the product. $P$,upon treatment with excess of $H_2O$ at room temperature,gives the product $Q$. Bromination of $Q$ in aqueous medium furnishes the product $R$. The compound $P$ upon treatment with an excess of phenol under basic conditions gives the product $S$.
The molar mass difference between compounds $Q$ and $R$ is $474 \ g \ mol^{-1}$ and between compounds $P$ and $S$ is $172.5 \ g \ mol^{-1}$.
$(1)$ The number of heteroatoms present in one molecule of $R$ is . . . . .
[Use: Molar mass (in $g \ mol^{-1}$): $H=1, C=12, N=14, O=16, Br=80, Cl=35.5$
Atoms other than $C$ and $H$ are considered as heteroatoms]
$(2)$ The total number of carbon atoms and heteroatoms present in one molecule of $S$ . . . . . .
[Use: Molar mass in $g \ mol^{-1}$]: $H=1, C=12, N=14, O=16, Br=80, Cl=35.5$
Atoms other than $C$ and $H$ are considered as heteroatoms
Give the answer for question $(1)$ and $(2)$.

Match the compounds given in List-$I$ with the items given in List-$II$.

List-$I$	List-$II$
$I.$ Benzenesulphonyl Chloride	$A.$ Zwitterion
$II.$ Sulphanilic acid	$B.$ Hinsberg reagent
$III.$ Alkyl Diazonium salts	$C.$ Dyes
$IV.$ Aryl Diazonium salts	$D.$ Conversion to alcohols

$(i)$ Write structures of different isomeric amines corresponding to the molecular formula,$C_{4}H_{11}N$. $(ii)$ Write $IUPAC$ names of all the isomers. $(iii)$ What type of isomerism is exhibited by different pairs of amines?

An aromatic compound $A$ on treatment with aqueous ammonia and heating forms compound $B$,which on heating with $Br_2$ and $KOH$ forms a compound $C$ of molecular formula $C_6H_7N$. Write the structures and $IUPAC$ names of compounds $A, B$,and $C$.

The product $(Y)$ of the following reaction is: