Number of $\pi$-bonds present in $B.H.C.$ ($Benzene$ $hexachloride$) are

Which of the following is a Friedel-Crafts reaction $(FCR)$?

Which one of the following gives a sooty flame on combustion?

Give the name and structure of an aromatic hydrocarbon with the molecular formula $C_{12}H_{10}$ which contains two benzene rings.

Which of the following compounds will undergo electrophilic substitution more readily than benzene?

What is the ratio of glyoxal to pyrualdehyde obtained in the ozonolysis of $o-xylene$ as shown in the reaction below?
$o-Xylene$ $\xrightarrow[{(2) Zn}]{{(1) O_3}} CHO-CHO \text{ (Glyoxal)} + CH_3CO-COCH_3 \text{ (2,3-Butanedione)} + CH_3CO-CHO \text{ (Pyrualdehyde)}$