Chapter 5 question 8

        I wanted to show one of the basic fundamental reactions of alkenes because you have to have the basics down do be able to do the more complicated synthesis problems later on. The reaction I chose was the addition of a hydrogen halide to an alkene. Specifically H-Br. Question 8 did not ask for the mechanism but it is still beneficial for us to know how we got to the final answer just as much as knowing what the final answer is.                                                 


        



The first step occurs when the the electrophilic H adds to an alkene carbon atom, forming a secondary carbocation. The bromide ion is set free to be left by itself. As you can see this particulate alkene is symmetrical so it does not matter which carbon gets the H because you get the same product either way. If the alkene was non symmetrical you would have to see which H would be removed to give the Markovnikov Product (which is when the hydrogen adds to the carbon with the  most number of hydrogens so the halide can add to the carbon that is the most substituted. )











        The next step the nucleophilic Br– adds to the carbocation intermediate, yielding the bromoalkane product.




Reference: http://www.saplinglearning.com