The major product of the reaction between 2-methyl-2-butene CH3C CH3 =C CH3 2 and HBr in an aqueous solution is 2-bromo-2-methylbutane CH3C CH3 Br C CH3 3 . This reaction follows Markovnikov's rule, where the hydrogen atom H from HBr will attach to the carbon with the most hydrogen atoms, and the bromine atom Br will attach to the carbon with the least hydrogen atoms.