Answer: 0-5°C.
- A 0-5°C
- B 25°C
- C 50°C
- D 100°C
Correct answer: A. 0-5°C
Explanation: Above ~5°C, diazonium salts decompose rapidly; they must be used immediately after preparation at 0-5°C.
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.