Answer: N-H...N bonds are weaker than O-H...O bonds.
- A N-H...N bonds are weaker than O-H...O bonds
- B amines cannot form any hydrogen bonds
- C amines always have a lower molar mass
- D amine molecules exist as ionic solids
Correct answer: A. N-H...N bonds are weaker than O-H...O bonds
Explanation: Nitrogen is less electronegative than oxygen, so the N-H...N hydrogen bonds in amines are weaker, giving lower boiling points.
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.