<human>:  I need help understanding the chemical reaction for saponification.
<bot>: Saponification is a chemical reaction in which an ester is heated with an alkali to form a salt and an alcohol. The alkali is usually a base such as sodium hydroxide or potassium hydroxide. The ester is typically a fat or oil, such as lard or olive oil. During saponification, the ester bonds are broken down into molecules of the acid and alcohol. The acid reacts with the base to form a salt, and the alcohol becomes the product of the reaction. This process is also known as "soap-making" because the product formed is generally a type of soap.