Explain with suitable example how the molecularity of a reaction Is different from the order of reaction ?

Explanation

Order is the sum of powers of the concentration terms in the rate law expression. Molecularity is the number of reacting species that must collide with each other simultaneously to bring about a chemical reaction.
To differentiate between the two, let us consider the reaction.
`underset("Excess")(CH_3COOC_2H_5)+H_2O overset(H^(+))(rarr)CH_3COOH+C_2H_5OH`
In this case molecularity of the reaction is two because it involves two reacting species i.e., ethyl acetate and water. However, the concentration of only ethyl acetate changes" during the reaction as water is taken in large excess.
Therefore, rate of reaction=`k[CH_3COO_2H_5]`
Thus order of reaction is one