the reactivity in a reaction follows the inverse principle of reactivity and selectivity.in a free radical reaction bromine is more selective as compared to chlorine which is more reactive.the selectivity in its attack of alkane by bromine of 3,2,1 degree are in the ratio of 1600:82:1 whereas for chlorine it is 5:3.8:1.
now since bromine is more selective therefore it will take more timeto react ans in this process more stable 3degree free radical of alkane will be formed whereas for chlorine it will reactive fastly giving no timefor rearrangement forming a mixtureof alkane.
thanks and regard
sunil kumar
ask iitian faculty
