Predict the major product(s) of the following reactions and explain their formation.

H3C - CH = CH2 HBr(Ph -CO-O)2H3C -CH =CH2 HBr


In presence of organic peroxides, the addition of HBr to propene follows anti Markowinkov's rule (or peroxide effect) to form 1-bromopropane (n-propyl bromide)
However, in absence of peroxides, addition of HBr to propene follows Markownikoff's rule and gives 2-bromopropane as major product.