Which of the following has the lowest heat of hydrogenation per mole?

Consider the following reaction:

$\mathrm{R}-\mathrm{CH}={\mathrm{CH}}_2+{\mathrm{IN}}_3^{}\to \mathrm{A},\mathrm{A}$ is:

 product; product will be:

 major product will be:

The most probable structure for $\left(\mathrm{P}\right)$ in the following reaction is:

Arrange the following in order of increase/decrease in boiling point.

$\begin{array}{c}{\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_3\\ \mathrm{I}\end{array}$  $\begin{array}{c}{\left({\mathrm{CH}}_3\right)}_2{\mathrm{CHCH}}_2{\mathrm{CH}}_3\\ \mathrm{II}\end{array}$ $\begin{array}{c}{\left({\mathrm{CH}}_3\right)}_4\mathrm{C}\\ \mathrm{III}\end{array}$