Question

In the presence of peroxide addition of HBr to propene takes place according to anti Markovnikov’s rule but peroxide effect is not seen in the case of HCl and HI. Explain.

Answer 1

Peroxide effect is not observed in addition of HCl and HI. This is due to the feet that the H—Cl bond being stronger than H—Br bond is not cleaved by the free radical whereas the H—I bond is weaker and iodine free radicals combine to form iodine molecules instead of adding to the double bond.