Explain and draw the mechanism of the nucleophillic substitution reaction between bromoethane and aqueous sodium hydroxide. How is this reaction different to the elimination reaction which may occur?

The d+ carbon on the bromoethane is susceptible to attack by the OH- nucleophile (negative ion with a lone pair)( the lone pair is very important as this carries out the attack!!!).

When the nucleophile attacks the C-Br bond breaks and the halide ion (Br-) is released. The OH- therefore replaces the Br in a substitution reaction.This process is sometimes known as hydrolysis.

(see drawn mechanism)

This is different to the elimination reaction because in the elimination reaction, the hydroxide OH- ion functions as a base.This means a proton is removed by the OH- and the halogen is removed, resulting in an alkene.

(see drawn mechanism)