Answer: 1° > 2° > 3°.
- A 1° > 2° > 3°
- B 2° > 1° > 3°
- C 3° > 2° > 1°
- D all are equal
Correct answer: A. 1° > 2° > 3°
Explanation: More N-H bonds mean more hydrogen bonding, so a primary amine boils highest and a tertiary (no N-H) lowest.
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.