Answer: Diazonium salt.
- A Diazonium salt
- B Amide
- C Nitrile
- D Imine
Correct answer: A. Diazonium salt
Explanation: Diazotisation with NaNO<sub>2</sub>/HCl at 0-5°C converts ArNH<sub>2</sub> to ArN2+Cl- (diazonium salt).
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.