The compound that does not undergo Friedel-Crafts alkylation reaction but gives a positive carbylamine test is :
- Aniline
- Pyridine
- N-methylaniline
- Triethylamine
Answer
(1) Aniline
Solution
Carbylamine test is given only by primary amines: RNH2 + CHCl3 + 3KOH RNC + 3KCl + 3H2O.
Aniline is a primary aromatic amine, so it gives the test. It does not undergo Friedel-Crafts reaction because the basic -NH2 group forms a salt with the Lewis acid AlCl3; the N acquires a positive charge, which strongly deactivates the ring.
Pyridine and triethylamine (3°) and N-methylaniline (2°) do not give the carbylamine test.
Answer: (1)