Organic Chemistry

When propene reacts with HBr the main product is 2-Brome butane(CH3-CH=CH2 + HBr ? CH3-CH(Br)-CH3) , but not 1-Bromo butane. We can explain this on the basis of the stability of the intermedite product forms during the reaction. This is an electrophillic addition reaction, that means the electrophile from HBr (H+) attacks the propene first. so there is a chance of formation of two intermediates (CH3-CH=CH2 + H+ > CH3-CH+-CH3(A) + CH3-CH2-CH2+(B)) So in the above rection intermediate product A is more stable than B this is because the positive charge in A is decreased by the two CH3 groups from both the sides. But if same reaction takes place in the presence of any peroxide then the main product will be 1-bromo propane. This is called Peroxide effect where the is a free radical addition reaction but not the electrophillic.