ELECTROPHILIC ADDITION TO UNSYMMETRICAL ALKENES The electrophilic addition of hydrogen halides to UNSYMMETRICAL alkenes produces two products because of the two different possibilities of adding the halide. According to MARKOVNIKOV'S RULE, the reaction proceeds via the more stable carbocation (carbonium) ion.  In the animation the first route is via a SECONDARY carbocation and the second route is via a PRIMARY carbocation. Secondary carbocations are more stable than primary carbocations so are formed more readily. Once formed, both carbocations react very quickly. The preferred product will be 2-bromopropane. To repeat, click on the REFRESH icon