Cambridge IGCSE Chemistry · Syllabus 0620 · Organic Chemistry
Ester
What is Ester?
An organic compound formed when a carboxylic acid reacts with an alcohol using an acid catalyst, containing the -COO- ester linkage, and named with the alkyl group from the alcohol first followed by the alkanoate stem from the acid.
This definition is part of the Organic Chemistry chapter in Cambridge IGCSE Chemistry.
Common mistakes with Ester
- “Ethanol plus methanoic acid gives ethyl methanoic acid.” Supplement 11.2.4 why it fails An ester name never keeps the word “acid”, and the two halves are easy to swap. correct Alkyl from the alcohol first, alkanoate from the acid second: ethanol gives “ethyl”, methanoic acid gives “methanoate”, so the ester is ethyl methanoate. Taught in 11.2.
- 4. “Ethanol plus methanoic acid gives ethyl methanoic acid.” Supplement 11.2.4 defect The word “acid” retained in an ester name. why An ester is not an acid; it has no acidic hydrogen. The acid's ending becomes -oate. repair Delete “ic acid” and write “ate”: ethyl methanoate. transfer Name the ester from butan-1-ol and propanoic acid, then say which parent gave each word.