JEE Main · 2023 · 11 Apr 2023 · Shift 1 · Compounds Containing Nitrogen

o-Phenylenediamine has two amino groups in ortho positions. When treated with ${\mathrm{HNO}}_2$ (nitrous acid), both amino groups are converted to diazonium groups. However, the ortho-diazonium groups are unstable and undergo intramolecular cyclization with loss of nitrogen to form benzotriazole. The major product X is benzotriazole, a five-membered heterocyclic ring fused to benzene containing three nitrogen atoms.