$2-\mathrm{chlorobutane}+{\mathrm{Cl}}_2\to {\mathrm{C}}_4{\mathrm{H}}_8{\mathrm{Cl}}_2$ (isomers)
Total number of optically active isomers shown by ${\mathrm{C}}_4{\mathrm{H}}_8{\mathrm{Cl}}_2$, obtained in the above reaction is ________.

The following reaction,

$\mathrm{R}-\mathrm{X}+\mathrm{NaI}\to \mathrm{R}-\mathrm{I}+\mathrm{NaX}$  where, $\mathrm{X}=\mathrm{Cl},\mathrm{Br}$ is known as

Identify the reagent(s) '$\mathrm{A}$' and condition(s) for the reaction :

Major product P of above reaction, is:

For the given reaction:

What is $\mathrm{A}$?

The major products, $\mathrm{P}$ and $\mathrm{Q}$, formed in the reactions given below are:

Identify $\mathrm{X}$ in the reaction given below

The major product (Q) of the below reactions is

The major product of the following reaction is: