The correct order of reactivity for the reaction involving the cleavage of the $C-X$ bond in the following compounds is:

What will be the major product $A$ in the following reaction?

The reaction in which $2$ molecules of chlorobenzene react with metallic sodium in the presence of dry ether to form biphenyl is an example of:

Which of the following reasons support that aryl halides are less reactive than alkyl halides towards nucleophilic substitution reactions?
$a)$ The formation of more stable arenium ion
$b)$ Partial double bond character of $C-X$ bond
$c)$ Longer $C-X$ bond
$d)$ $sp^2$ carbon bonded to $X$ is more electronegative

The reaction between chlorobenzene and chloral in the presence of concentrated sulphuric acid produces

Identify $Y$ in the following reaction.