Which carboxylic acid is also known as acetic acid?

Ethanoic acid is the systematic IUPAC name for the carboxylic acid commonly known as acetic acid. It has the chemical formula CH3COOH, which indicates it consists of a two-carbon chain with a carboxyl functional group (-COOH) attached to it. This structure characterizes it as the simplest carboxylic acid with two carbon atoms.

Acetic acid is widely known for its use in cooking and food preservation (like vinegar) and plays a significant role in various industrial processes. The other options represent different carboxylic acids with distinct structures and names: butanoic acid contains four carbon atoms, propanoic acid has three, and methanoic acid has one. Understanding these differences is essential in identifying and naming organic compounds accurately.