Carboxylic acid
The carboxylic acid has the -COOH group (carbonyl + hydroxyl on the same carbon) at the end of the chain. It's the highest-priority functional group in IUPAC nomenclature — if present, it always becomes the name's suffix, never a prefix.
General formula
R–COOH
Naming rule
Name = acid + main chain (including the -COOH carbon) + suffix -oic acid. No locant needed — the -COOH is always at position 1.
Examples
| Name | Formula |
|---|---|
| Methanoic acid (formic) | HCOOH |
| Ethanoic acid (acetic) | CH₃COOH |
| Propanoic acid | C₂H₅COOH |
| Benzoic acid | C₆H₅COOH |