Hydrolysis of an ester is an example for

The chemical reaction for ester hydrolysis is shown below.

${\text{CH}}_{\text{3}}{\text{COOC}}_{\text{2}}{\text{H}}_{\text{5}}{\text{+H}}_{\text{2}}\text{O}\left(\text{excess}\right)\to {\text{CH}}_{\text{3}}\text{COOH}+{\text{C}}_{\text{2}}{\text{H}}_{\text{5}}\text{OH}$

The number of reactant molecules is 2.  So, molecularity is 2. 

In the ester hydrolysis reaction, water${\text{H}}_{\text{2}}\text{O}$ is taken in the excess amount .Hence, the order of reaction is 1(first order).

Therefore, the reaction is called as pseudo unimolecular reaction or pseudo first order reaction.