Question

Chlorination of methane does not occur in dark because:

• A. methane can form free radicals in presence of sunlight only
• B. to get chlorine free radicals from $C{l}_2$ molecules energy is required. It cannot happen in dark.
• C. substitution reaction can take place only in sunlight and not in dark
• D. termination step cannot take place in dark. It requires sunlight.

Answer 1

The correct option is B to get chlorine free radicals from $C{l}_2$ molecules energy is required. It cannot happen in dark.

Chlorination of methane is a free radical substitution. To get chlorine free radical, UV light is required to initiate the substitution reaction, which is provided by sunlight.

$C{l}_2\underset{}{\overset{hv}{\to }}C{l}^{\bullet }+C{l}^{\bullet }$