Nitrobenzene obtained from benzene where ${\mathrm{HNO}}_3$ and${\mathrm{H}}_2{\mathrm{SO}}_4$ takes part in the reaction. What is the behaviour of ${\mathrm{HNO}}_3$ like-

Among the following, the reaction that proceeds through an electrophilic substitution, is:

 The major product of the following reaction is:

The major product obtained in the given reaction is:

In the following reaction sequence the major products $\mathrm{A}$ and $\mathrm{B}$ are :

In the following reactions

$\mathrm{X}$ and $\mathrm{Y}$, respectively, are:

The major product of the following reaction is: