Answer: aniline.
- A toluidine
- B pyridine
- C aniline
- D anisidine
Correct answer: C. aniline
Explanation: C<sub>6</sub>H<sub>5</sub>NH<sub>2</sub>, systematically benzenamine, is universally called aniline.
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.