The SN2 Reaction H H H-0:+ H-C-j: H-O-C-H H H hydroxide iodomethane methanol iodide (nucleophile) (substrate) (product) (leaving group) The halogen atom on the alkyl halide is replaced with the nucleophile (HO). ● Since the halogen is more electronegative than carbon, the C-l bond breaks heterolytically and the iodide ion leaves. 25 2013 Pearson Education Inc. The SN2 Reaction • The halogen atom on the alkyl halide is replaced with the nucleophile (HO- ). • Since the halogen is more electronegative than carbon, the C—I bond breaks heterolytically and the iodide ion leaves. 25 © 2013 Pearson Education Inc