Answer:
See Explanation and image attached
Step-by-step explanation:
Methane is an alkane. The commonest chemical reaction that alkanes undergo is substitution. During a substitution reaction, one or more atoms of hydrogen is/are replaced in the alkane.
In methane, in the presence of sunlight and molecular chlorine gas, a homolytic fission of Cl2 occurs to yield chlorine radicals in an initiation step.
The propagation steps involve reaction of the methane with chlorine radicals. Certain intermediates continue to be formed along the way until the tetrachlorination product is finally obtained.