Which of the following gives only one monosubstituted product upon further electrophilic substitution?

"The presence of an electron-withdrawing group $\left( -NO_2 \right)$ at the ortho and para positions in haloarenes increases the reactivity of haloarenes towards nucleophilic substitution reactions." Prove this with an example.

The two reactions involved in the conversion of benzene diazonium chloride to diphenyl are respectively:

The product obtained by the nitration of nitrobenzene is.....

$C_6H_6Cl_6$,on treatment with alcoholic $KOH$,yields

In which of the following compounds does electrophilic attack occur at ortho and para positions?