What is the IUPAC name of acetone?

The IUPAC name of acetone is propanone, more explicitly written as propan-2-one. Its three-carbon chain contains a ketone group, and the carbonyl carbon occupies position 2.

Acetone has the structural formula CH₃COCH₃ and is the simplest ketone. In systematic naming, “prop-” identifies the three-carbon chain and “-one” identifies the ketone functional group. Because the carbonyl must be in the middle of a three-carbon chain, the locant 2 is often omitted in the shorter form “propanone.”

Acetone is also a retained and extremely common name, so it is not merely an informal nickname. It is a colorless, volatile, highly flammable liquid that mixes readily with water and is used as a solvent, including in some nail-polish removers and laboratory processes. A frequent mistake is to choose propanal: that compound has the same formula as acetone but contains an aldehyde group rather than a ketone group.