Answer: Diethylamine (secondary amine).
- A Diethylamine (secondary amine)
- B Ethylamine (primary amine)
- C Triethylamine (tertiary amine)
- D Aniline
Correct answer: A. Diethylamine (secondary amine)
Explanation: Secondary amines give N,N-disubstituted sulfonamides with no N-H; this is insoluble in NaOH.
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.