When ethanol is treated with benzene diazonium chloride it forms

A) Azo compound

When ethanol (C₂H₅OH) is treated with benzene diazonium chloride (C₆H₅N₂⁺Cl⁻) under alkaline conditions, a coupling reaction does not normally occur as with phenols or aromatic amines, because ethanol lacks an activated aromatic ring.

However, if the question refers to aromatic alcohols (like phenol), diazonium salts undergo azo coupling to form azo compounds (Ar–N=N–Ar′), which are highly colored and used in dyes. In the case of ethanol, it may simply result in decomposition of the diazonium salt, producing nitrogen gas and a substituted benzene derivative under specific conditions.

Why it matters:

• Diazonium salts are unstable and readily release N₂ gas.
• In synthetic chemistry, aromatic diazonium salts are valuable intermediates for introducing various substituents onto an aromatic ring.

Exam tip: If you see “benzene diazonium chloride” and “phenol” or “aniline,” think of azo dye formation; with ethanol, expect decomposition or no significant coupling due to the lack of an aromatic system.