Question

Benzene diazonium chloride on reaction with phenol in weakly basic medium gives

• A. Azobenzene
• B. Benzene
• C. Chlorobenzene
• D. p-hydroxyazobenzene

Hint:

Benzene diazonium chloride is a weak electrophile and undergoes an azo coupling reaction with electron rich aromatic compounds such as phenol.

Answer 1

The Correct Option is D

Concept: Benzene diazonium chloride is a weak electrophile and undergoes an azo coupling reaction with electron rich aromatic compounds such as phenol. In a weakly basic medium the phenol is partly converted to the more reactive phenoxide ion, and coupling occurs at the para position (highest electron density, least steric hindrance). This forms an azo compound p-hydroxyazobenzene, which is an orange dye.
Answer: Option (D) - because azo coupling of the diazonium salt with phenol occurs at the para position to give p-hydroxyazobenzene.