How do you account for formation of ethane during chlorination of methane ?

Explanation

Chlorination of methane is a free radical reaction which occurs by the following mechanism :

From the above mechanism, it is evident that during propagation step, `oversetdot(CH_3)` free radicals are produced which may undergo three reactions , i.e. (i)-(iii). In the chain termination step , the two `oversetdot(CH_3)` free radicals combine together to form ethane `(CH_3-CH_3)` molecules .