Methane undergoes a substitution reaction in the presence of sunlight and chloride to produce

In the presence of sunlight, chlorine is added to hydrocarbons(alkane). Chlorine can replace by hydrogen atoms one by one. It is called a substitution reaction. Example: Methane reacts with chloride in the presence of sunlight from Chloromethane and Hydrochloric acid.

${\mathrm{CH}}_4+{\mathrm{Cl}}_2\stackrel{\mathrm{h\gamma }}{\to }{\mathrm{CH}}_3\mathrm{Cl}+\mathrm{HCl}$