What is the common name for the simplest ketone, propan-2-one?

The simplest ketone, propan-2-one, is commonly known as acetone. Acetone has the molecular formula C3H6O and is characterized by its structure consisting of a carbonyl group (C=O) flanked by two methyl groups (CH3). This configuration is integral to its identity as a ketone.

The reason acetone is associated with propan-2-one is due to its IUPAC naming convention, in which the "propan-" refers to the three carbons present, and the "-2-one" indicates the presence of the ketone functional group at the second carbon. Acetone is widely recognized and used as a solvent in various applications, including nail polish remover and industrial processes.

The other options listed do not reflect the correct common name for propan-2-one. Butanone refers to a four-carbon ketone, propanal is an aldehyde rather than a ketone, and isobutanol is an alcohol, specifically a branched chain of four carbons. Thus, acetone remains the correct and widely accepted common name for propan-2-one in organic chemistry.