Answer: LiAlH 4.
- A LiAlH<sub>4</sub>
- B NaBH<sub>4</sub>
- C HCl
- D KMnO<sub>4</sub>
Correct answer: A. LiAlH<sub>4</sub>
Explanation: LiAlH<sub>4</sub> reduces nitriles to primary amines (RCN → RCH<sub>2</sub>NH<sub>2</sub>).
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.