In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (h) of at least one acidic hydroxyl group (âˆ'oh) of that acid is replaced by an organyl … In this tutorial you will learn about the basic properties and structure of an ester functional group. You will also learn about esterification and its mechanism.

The diagram shows the relationship between the ethanoic acid, the ethanol and the ester. Key takeaway an ester has an or group attached to the carbon atom of a carbonyl group.