When HBr is dissolved in solution it dissociates in its two major components: H+ and Br-. The acidic environment promotes nucleophilic of the alkenes to the electrophilic protons to form an intermediate carbocation. The carbocation is the subsequently quenched by nucleophilic attack of the bormide ion to give the desired product. When predicating the regiochemistry for the addition of HBr into alkenes, the H+ will added to the carbon atom that generates the most sable carbocation – Markovnikov’s rule. Therefore the addition of HBr to 2-methylpropene would give 2-bromo-2-methylpropane.