Q.

Which of the following can be used as the halide component for Friedel–Crafts reaction            [2016]

1 Chlorobenzene  
2 Bromobenzene  
3 Chloroethene  
4 Isopropyl chloride  

Ans.

(4)

Friedel–Crafts reaction:

Chlorobenzene, bromobenzene and chloroethene are not suitable halide components as C–X bond acquires some double bond character due to resonance of lone pair of electrons with π-bond.