JEE Advanced · 2013 · 02 Jun 2013 · Paper 2 · Hydrocarbons

The reaction involves bromination of phenol in the presence of ${\mathrm{SO}}_{3}H$ group. The $-OH$ group is strongly activating and ortho/para-directing, while $-{\mathrm{SO}}_{3}H$ is a very good leaving group. Under these conditions, the $-{\mathrm{SO}}_{3}H$ group is displaced, and bromination occurs at the activated positions. The major product $\mathbf{Q}$ is 2,4,6-tribromophenol, formed after desulfonation and bromination at all activated positions.