Acetic acid , systematically named
ethanoic acid , is an
organic compound with the
chemical formula CH
3COOH (also written as CH
3CO
2H or C
2H
4O
2). It is a colourless liquid that when undiluted is also called
glacial acetic acid.
Vinegar is roughly 3–9% acetic acid by volume, making acetic acid the main component of vinegar apart from water. Acetic acid has a distinctive sour taste and pungent smell. Besides its production as household vinegar, it is mainly produced as a precursor to polyvinylacetate and
cellulose acetate. Although it is classified as a
weak acid, concentrated acetic acid is corrosive and can attack the skin.