Addition to HBr to propene
(unsymmetrical alkene) follows Markovnikov Rule according to which the negative
part of the addendum gets attached to that C atom which possesses lesser number
of hydrogen atoms.
Addition of
HBr to unsymmetrical
alkenes like propene in the
presence of light or peroxide takes place
contrary to the
Markovnikov rule. This
so happens only with HBr but not with HCl and HI. This Addition of
HBr to propane
in the presence
of benzoyl peroxide follows Anti-Markownikov Rule or Peroxide effect or
Kharash Effect.
The secondary free radical obtained
in (iii) in the above mechanism happens to be more stable than the primary one
hence, explains the formation of 1-bromopropane.
