Chemistry - Biomolecules Question with Solution | TestHub

Sulphanilic acid is $p$-aminobenzenesulphonic acid, which contains both an acidic group ($-S{O}_{3}H$) and a basic group ($-N{H}_2$).

In aqueous solution or in the solid state, the acidic $-S{O}_{3}H$ group donates a proton ($H^{+}$) to the basic $-N{H}_2$ group. This internal acid-base reaction leads to the formation of a dipolar ion, known as a zwitterion.

The resulting zwitterion has a positively charged ammonium group ($-N{H}_3^{+}$) and a negatively charged sulphonate group ($-S{O}_3^{-}$) at the para positions of the benzene ring.

Looking at the given options, the structure with $-N{H}_3^{+}$ and $-S{O}_3^{-}$ at para positions represents the zwitterion of sulphanilic acid.

Answer: