How many hydroxy groups are present in hydroxyquinol?

Which xylene is most easily sulphonated?

Which of the following is an example of a non-benzenoid aromatic compound?

Carbon-Carbon bond length in benzene is $.....$ $\mathring{A}$

What are the major products obtained in each case when compounds $P, Q,$ and $S$ are nitrated using a mixture of $HNO_3/H_2SO_4$?

The product obtained by the hydrogenation of $1 \ mol$ of benzene with $3 \ mol$ of $H_2$ in the presence of a $Ni$ catalyst at high temperature is...