preparation of alkyl halides in laboratory is least preferred by .

Options

A. Halide exchange
B. Direct halogenation of alkanes
C. Treatment of alcohols
D. Addition of hydrogen halides to alkenes

Answer

B

Explanation

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)(rarr)CH_3Cl overset(Cl_2)(rarr) CH_2Cl_2 overset(Cl_2)(rarr) CHCl_3 overset(Cl_2)(rarr)"CCl"_4`