Reactivity of Halogenoalkanes (AQA A-Level Chemistry): Revision Notes
📚 Revision Notes
3.3.1 Reactivity of Halogenoalkanes
infoNote
Halogenoalkanes are organic compounds containing carbon-halogen (C-X) bonds, where X is a halogen such as chlorine, bromine, or iodine. Their reactivity is largely influenced by the bond enthalpy of the carbon-halogen bond, and they primarily undergo nucleophilic substitution reactions. Understanding how these reactions occur is key to predicting the behaviour of halogenoalkanes.
Carbon-Halogen Bond and Reactivity
The reactivity of halogenoalkanes depends on the strength of the carbon-halogen bond. The bond enthalpy of the carbon-halogen bond decreases as you move down Group 7 of the periodic table:
- bond: Strongest bond with the highest bond enthalpy. This means that fluoroalkanes are the least reactive in nucleophilic substitution reactions because the bond is harder to break.
- bond: Weakest bond with the lowest bond enthalpy. Iodoalkanes are the most reactive in nucleophilic substitution because the bond is easier to break.