Mechanism of Addition of HX Step 1:Protonation of the double bond. HH HH CH3一CC一CH3 CH3-C-C-CH3+:Br: H-Br: H Copyright 2010 Pearson Prentice Hall.Inc. Step 2:Nucleophilic attack of the halide on the carbocation. HH HH CH3一 C一CH3+:Br CH3-C- CH H H :Br: Copyright2010 Pearson Prentice Hall,Inc Chapter 8 6Chapter 8 6 Mechanism of Addition of HX Step 1: Protonation of the double bond. Step 2: Nucleophilic attack of the halide on the carbocation