User:Zainab maki/sandbox

ALKYL HALIDES The influence of bond polarity: Out of the four halogens, fluorine is the most electronegative and iodine the least. This means that the electron pair in the C-F bond will be dragged most towards the halogen end. Let’s look at the methyl halides as a simple example: d+ d- d+ d- d+ d- F Cl Br l No polarity One of the important set of reactions of haloalkanes is substitute reactions, which involves replacing the halogen by something else. These reactions involve: (a) The carbon-halogen bond breaking to give positive and negative ions. The ion with the positively charged carbon atom then reacts with something either fully or slightly negatively charged. Or, (b) Something either fully or negatively charged attracted to the slightly positive carbon atom and pushing off the halogen atom. The thing that governs the reactivity is the strength of the bonds which have to be broken. It is difficult to break a C-F bond, but easy to break a C-I one.