The number of nitrogen atoms in the major organic product, Q, of the reaction given below is _____.

The compound shown is benzene-1,2-diamine (o-phenylenediamine) treated with sodium nitrite (NaNO₂) and concentrated HCl at 273–278 K, which is a typical setup for diazotization.

Reaction explanation:

• Both −NH₂ groups undergo diazotization with NaNO₂/HCl to form a diazonium salt.
• However, when phenylenediamine (with both groups ortho) is treated with nitrous acid, it forms a cyclic compound called benzotriazole as the major product.
• Benzotriazole has a ring containing three nitrogen atoms.

Answer: The number of nitrogen atoms in the major organic product Q is 3.