Chapter 8 ? 2010, Prentice Hall Organic Chemistry, 7th Edition L. G. Wade, Jr. Reactions of Alkenes Chapter 8 * Bonding in Alkenes Electrons in pi bond are loosely held. The double bond acts as a nucleophile attacking electrophilic species. Carbocations are intermediates in the reactions. These reactions are called electrophilic additions. Chapter 8 Chapter 8 * Electrophilic Addition Step 1: Pi electrons attack the electrophile. Step 2: Nucleophile attacks the carbocation. Chapter 8 Chapter 8 * Types of Additions Chapter 8 Chapter 8 * Addition of HX to Alkenes Step 1 is the protonation of the double bond. The protonation step forms the most stable carbocation possible. In step 2, the nucleophile attacks the carbocation, forming an alkyl halide.