At 25C the free radical chlorination of isobutene yields 36% tert-butyl chloride and 64%isobutyl chloride. However at 127C free radical brominating of the same compound yields only trace amount of isobutyl bromide and 99% tert-butyl bromide, even though the ease of formation and free radical stability is the same fro chlorination and brominating. Discuss the cause for these differences in the ratio of the product? Consider that there activity ratio of the products for chlorination and brominating are 5:3.8:1 and 1600:82:1 respectively.