Answer: Hofmann elimination to give alkene.
- A Hofmann elimination to give alkene
- B Reduction back to the original tertiary amine
- C Oxidation of the nitrogen to an N-oxide
- D A Stevens-type rearrangement of the alkyl groups
Correct answer: A. Hofmann elimination to give alkene
Explanation: Heating quaternary ammonium hydroxide gives Hofmann elimination: alkene + tertiary amine + water.
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.