An aliphatic amine with molar mass $73 \mathrm{g}$ on heating with excess of ${\mathrm{CH}}_3\mathrm{I}$ gave a quaternary salt. Which of the following amine follow this data?

In the reaction sequence

X and Y are, respectively,

The major product obtained in the following reaction is:

What will be the major product in the following mononitration reaction?

The major product of the following reaction is:

Scheme $1$ and $2$ describe the conversion of $\mathrm{P}$ to $\mathrm{Q}$ and $\mathrm{R}$ to $\mathrm{S},$ respectively. Scheme $3$ describes the synthesis of $\mathrm{T}$ from $\mathrm{Q}$ and $\mathrm{S}.$ The total number of $\mathrm{B}\mathrm{r}$ atoms in a molecule of $\mathrm{T}$ is

Scheme $1$:



Scheme $2$:



Scheme$3$:

The major product formed in the reaction given below will be :