Neucleophilic substitution reactions
...an atom or group of atoms is replaced by a nucleophile (an electron pair donor)
During hydrolysis, the halogen atom is replaced by the hydroxide ion. The substitution takes place as follows:
- the hydroxide ion, OH, has a lone pair of electrons. donated to the electron-deficient carbon atom in the halogenoalkane. This isneucleophilic attack.
- The donation of the electron pair leads to the formation of a new covalent bond between the oxygen atom of a new covalent bond between the oxygen atom of the hdydroxide ion and the carbon atom.
- The carbon-halogen, bond breaks by heterolytic fission. Both electrons from the bond move to the halogen, forming a halide ion.
Rate of hydrolysis of primary halogenoalkanes
The rates of hydrolysis for different halogenoalkanes can be determined using an experiment... The halogenoalkane is heated with aqueous silver nitrate, with ethanol added...
- Water in the mixture behaves as the neucleophile
- The ethanol acts as a common solvent, ensuring that the halogenoalkanes and aqueous silver nitrate mix together and react.
As the hydrolysis reaction takes…