Answer: ArCl or ArBr using Cu and HX.
- A ArCl or ArBr using Cu and HX
- B ArCN using CuCN as frequently described
- C Azo dye in most textbook accounts
- D Phenol during normal conditions
Correct answer: A. ArCl or ArBr using Cu and HX
Explanation: Gattermann reaction uses Cu powder and HCl/HBr (instead of CuCl/CuBr) to replace diazonium with halide.
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.