Answer: p-aminoazobenzene.
- A p-aminoazobenzene
- B phenol
- C benzene
- D chlorobenzene
Correct answer: A. p-aminoazobenzene
Explanation: Azo coupling at the para position of aniline gives the yellow dye p-aminoazobenzene.
In aniline, the nitrogen's lone pair is pulled into the benzene ring through resonance, leaving less electron density available to accept a proton - which is why aniline is a much weaker base than methylamine, where the lone pair is fully available.
Concept context
Nitrogen-containing organic compounds. Covers classification (primary, secondary, tertiary), basicity comparison, preparation methods, and reactions including diazotization and coupling, key for understanding dyes and pharmaceuticals.