Type of reaction: Free radical substitution reaction. It is a monosubstitution reaction because there is only one hydrogen atom in alkane is substituted by halogen free radical.
Step 1: Initiation step β’ In the present of uv light/heat, the covalent bond of Cl2 undergoes homolytic cleavage to produce free radicals. Function of uv light: provide energy for homolytic cleavage of Cl2
Step 2: Chain Propagation Step β’ Cl free radicals collide with methane to form HCl and methyl free radicals. Methyl free radicals react with Cl2 to form haloalkane and generate the chlorine free radicals
Step 3: Chain Termination Step β’ The reaction stops when the two free radicals collide and combine with one another