The addition of $Cl_2$ to benzene in the presence of $AlCl_3$ is an example of:

Given below are two statements:
Statement $I$: Nitration of benzene involves the following step:
$H-O^+(H)-NO_2 \rightleftharpoons H_2O + NO_2^+$
Statement $II$: Use of Lewis base promotes the electrophilic substitution of benzene.
In the light of the above statements,choose the most appropriate answer from the options given below:

An aromatic compound of molecular formula $C_6H_4Br_2$ was nitrated,and three isomers of formula $C_6H_3Br_2NO_2$ were obtained. The original compound is:

The reaction of toluene with chlorine in the presence of light gives

$A$ hydrocarbon does not decolorize alkaline $KMnO_4$ solution and does not give a precipitate with ammoniacal silver nitrate. This hydrocarbon is .......

The number of $\pi$-bonds and $\sigma$-bonds present in naphthalene are respectively