The ester formed from acetic acid and n-pentyl alcohol is pentyl acetate. The reaction between acetic acid and n-pentyl alcohol to form pentyl acetate is an example of an esterification reaction, which is a type of condensation reaction. In this reaction, the carboxylic acid group of acetic acid reacts with the hydroxyl group of n-pentyl alcohol to form an ester bond, releasing water as a byproduct. The general equation for this reaction is:

carboxylic acid + alcohol → ester + water

In this case, the specific reaction is:

acetic acid + n-pentyl alcohol → pentyl acetate + water

The product of this reaction, pentyl acetate, is a fragrant compound with a fruity odor. It is commonly used as a flavoring agent in foods and beverages, and it is also used in the production of perfumes and cosmetics.