What is correct about monochloro products of compound '$\mathrm{X}$'?

Which of the following is a free radical substitution reaction?

Isomers of hexane, based on their branching, can be divided into three distinct classes as shown in the figure.

The correct order of their boiling point is

Identify the decreasing order of boiling point of alkanes

(i) $\mathrm{n}$-pentane

(ii) Isopentane

(iii) Neopentane

The total number of monohalogenated organic products in the following (including stereoisomers) reaction is

$$\begin{gathered} \underset{(\mathrm{Simplest} \mathrm{optically} \\ \mathrm{active} \mathrm{alkene})}{\mathrm{A}} \underset{\left(\mathrm{ii}\right) {\mathrm{X}}_2/∆}{\overset{\left(\mathrm{i}\right) {\mathrm{H}}_2/\mathrm{Ni}/∆}{\to }} \end{gathered}$$

Identify $A$ in the given chemical reaction.

Which hydrogen in compound $\left(E\right)$ is easily replaceable during bromination reaction in presence of light ?