Which of the following compounds upon oxidation gives isophthalic acid?

Benzene undergoes substitution reaction more easily than addition because:

Benzene on treatment with a mixture of conc. $HNO_3$ and conc. $H_2SO_4$ at $100 \ ^oC$ gives

For the electrophilic aromatic substitution reaction on the benzene ring,the substituents are $-CH_3$,$-CH_2Cl$,$-CHCl_2$,and $-CCl_3$. What is the increasing order of reactivity towards electrophilic substitution?

Which equation represents an example of Friedel-Crafts reaction?

An aromatic compound,among other things,should have a $\pi$-electron cloud containing $(4n + 2)$ electrons,where $n$ cannot be: