Question

Why chlorination of methane is not possible in dark?

Answer 1

1. Chlorination of methane is a free radical substitution reaction.
2. Before chlorine reacts with methane, the Cl-Cl single bond must break to form free radicals and this can only be done in the presence of ultraviolet light.
3. In dark, chlorine-free radicals formation is not possible and so chlorination of methane is not possible in dark.
4. The ultraviolet light is a source of energy and is being used to break of Cl-Cl and produce Cl free radical Free radicals which can attack methane. in dark, this is not possible.