Identify the intermediate leads to the major product for the reaction of 2-methyl-2-butene with hydrogen bromide in the presence of peroxide.

II

Explanation:

We must have a good idea of the fact that there are two mechanisms that come into play when we are discussing about the addition of hydrogen halides to alkenes. The first is the ionic mechanism and the second is the radical mechanism.

The ionic mechanism is accounted for by the Markovnikov rule while the radical mechanism occurs in the presence of peroxides and is generally referred to as anti Markovnikov  addition.

The intermediate in anti Markovnikov  addition involves the most stable radical, in this case, it is a tertiary radical as shown in the images attached. The most stable radical is II hence it leads to the major product shown in the other image.