What is the IUPAC name for formaldehyde?

Formaldehyde is the simplest aldehyde and consists of a one-carbon aldehyde group with the chemical formula CH2O. The IUPAC nomenclature for aldehydes is based on the number of carbon atoms in the longest carbon chain that includes the aldehyde functional group, denoted by the suffix "-al."

In the case of formaldehyde, the compound contains just a single carbon atom. Therefore, the name is derived from the root name for one carbon, "meth-," combined with the aldehyde suffix to form "methanal." This nomenclature clearly indicates that there is one carbon atom and that it is an aldehyde.

The other names mentioned relate to different aldehydes, where butanal refers to a four-carbon aldehyde, ethanal to a two-carbon aldehyde, and propanal to a three-carbon aldehyde. Each of these is derived from their respective carbon chain lengths, leading to formaldehyde being uniquely identified as methanal in IUPAC terminology.