Give the major organic product formed when hydrogen bromide reacts with each of the alkene...

Give the major organic product formed when hydrogen bromide reacts with each of the alkenes in Problem 6.4 in the absence of peroxides and in their presence.

Sample Solution (a) The addition of hydrogen bromide in the absence of peroxides exhibits a regioselectivity just like that of hydrogen chloride addition; Markovnikov's rule is followed.

Under free-radical conditions in the presence of peroxides, addition takes place with a regioselectivity opposite to that of Markovnikov's rule.