Q.

The compound that does not undergo Friedel–Crafts alkylation reaction but gives a positive carbylamine test is             [2024]

1 aniline  
2 pyridine  
3 N-methylaniline  
4 triethylamine  

Ans.

(1)

Aniline does not undergo Friedel–Crafts reaction (alkylation and acetylation) due to salt formation with aluminium chloride, the Lewis acid, which is used as a catalyst. Due to this, nitrogen of aniline acquires positive charge and hence acts as a strong deactivating group for further reaction. Aniline, being a primary amine, gives positive carbylamine test.