Benzene reacts with chlorine to form benzene hexachloride in the presence of:

When acetylene is passed through a red hot iron tube,compound $X$ is formed. Which one of the following reactions will yield $X$ as the major product?

The compound that is most reactive towards electrophilic nitration is

Which of the following compounds or ions is not aromatic?

Which active species is involved in the nitration of benzene with concentrated nitric acid and concentrated sulfuric acid?

Hydrogenation of naphthalene $(P)$ with excess hydrogen gas stops cleanly at $1, 2, 3, 4-$ tetrahydronaphthalene $(Q).$ What conclusion can be drawn from this experiment?