What is the common name for propanoic acid?

Propanoic acid is a straightforward name derived from its structure, which consists of a three-carbon chain (prop-) with a carboxylic acid functional group (-COOH) at one end. The common naming convention for carboxylic acids typically combines the prefix that indicates the number of carbon atoms with the suffix "-ic acid."

In this case, "prop-" refers to the three carbon atoms in the chain, and when combined with the "-ic acid" suffix, it clearly indicates propanoic acid. The other options refer to different acids with distinct carbon chain lengths and structures: benzonic acid is a derivative of benzene with a carboxylic group, acetic acid contains two carbons, and methanoic acid consists of only one carbon. Therefore, when correctly identifying propanoic acid, it is essential to recognize how the naming correlates to the number of carbons and the functional group present.