$90 \ g$ of ethylamine on reaction with methyl chloride produces a tertiary amine as the exclusive product. The amount of methyl chloride required is:
$[\text{Given atomic masses in amu}: H=1, C=12, N=14, Cl=35.5]$ (in $g$)

$(i)$ 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?

Given below are two statements:
Statement-$I$ : Oxidation of $p$-nitrotoluene with acidic $KMnO_4$ gives an acid that is stronger than benzoic acid.
Statement-$II$ : Reduction of $p$-nitrotoluene with $Sn/HCl$ followed by neutralization gives an amine that is more basic than aniline.
In light of the above statements, choose the most appropriate answer from the options given below.

Among the compounds given below,the order of basicity is:
$(I)$ Piperidine
$(II)$ Pyridine
$(III)$ Morpholine
$(IV)$ Pyrrole

The compounds $X$ and $Y$ are respectively:

Identify the product $B$ in the following reaction:
$C_6H_5NH_2$ $\xrightarrow[0^\circ-5^\circ C]{NaNO_2/HCl} A$ $\xrightarrow{Ph-N(CH_3)_2} B$