Question

preparation of alkyl halides in laboratory is least preferred by .
A. Halide exchange
B. Direct halogenation of alkanes
C. Treatment of alcohols
D. Addition of hydrogen halides to alkenes

Answer 1

Correct Answer - B
Direct halogenation of alkenes are not preferred because in it a mixture of monohalogen, dihalogen, trihalogen and tetrahalogen substituted products are obtained which are difficult to separate.
e.g. `CH_(4)overset(Cl_(2))toCH_(3)Cloverset(Cl_(2))toCH_(2)Cl_(2)overset(Cl_(2))toCHCl_(3)overset(Cl_(2))toC Cl_(4)`.