Describe the mechanism of the free radical substitution of methane by chlorine in sunlight.

The reaction has three stages. Initiation: sunlight splits a chlorine molecule homolytically into two chlorine radicals. Propagation: a chlorine radical abstracts a hydrogen atom from methane to give a methyl radical and hydrogen chloride, and the methyl radical then attacks a chlorine molecule to give chloromethane and a fresh chlorine radical. Termination: two radicals combine and the chain ends.

No citable source has been recorded for this record. Treat it as practice material, not as fact.

Explanation

Because the chain continues, further substitution gives di-, tri- and tetrachloromethane.