Identify the diazonium group in the diazonium salt ArN2+Br−.

The correct answer is Option (2) → N₂⁺

In \( \ce{ArN2^+Br^-} \), Ar is the aryl group and \( \ce{Br^-} \) is the anion; the \( \ce{N2^+} \) part joined to the aryl group is the diazonium group.

NCERT (2026-27 edition):
II. DIAZONIUM SALTS – “The diazonium salts have the general formula R N₂⁺ X^– where R stands for an aryl group and X^– ion may be Cl^–, Br^–, HSO₄^–, BF₄^–, etc. … The N₂⁺ group is called diazonium group.”