Addition HBr to propene yields 2-bromopropane, while in the presence of benzoyl peroxide, the same reaction yields 1-bromopropane. Explain and give mechanism.

Explanation

HBr directly add to the propane, according to Markovnikov's rule. While in the presence of benzoyl peroxide HBr to propene according to anti Markovnikov rule.
Markovnik's rule: This rules states that when an unsymmetrical reagent adds to a double bond. the +Vve part of the adding reagent attaches itself to a carbon of the double bond so as to give the more table carbocation as an intermediate.

Anti markovnikov's rule (or) Kharasch effect: In presence of peroxide, addition of hydrogen halides to as unsymmetrical alkenes takes places in such a way that hydrogen atom becomes attached to the carbon atom having the fewer number of hydrogen atoms.
`underset("Propene")(CH_(3)-CH=CH_(2)+HBr) overset((C_(6)H_(5)CO)_(2)O_(2))to underset("1-Bromopropane")(CH_(3)-CH_(2)-CH_(2)Br)`