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 $Cl_2$ 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

Answer: (B)

Chlorination of methane is free radical substitution. To get chlorine free radical energy is required which is provided by sunlight to initiate the reaction.
$Cl _{2} \xrightarrow{h v} Cl ^{\bullet}+ Cl ^{\bullet}$