Answer:
Remove exess water
Explanation:
The reaction involved is an esterification reaction. Esterification is a reaction in which alcohol and carboxylic acid reacts to yield an ester and water. It is analogous to the inorganic neutralization reaction.
According to Le Chatelier's principle , one method of driving the equilibrium towards the forward reaction is by removal of one of the products. In this case, if water is removed, the forward reaction is favoured.
Fe2O3 because O has a -2 charge and Fe and +3, you want the charges to equal each other so if you have 2 Fe with +3 charge the charge becomes 6 if you have 3 O with -2 charge the charge becomes 6.