Carboxylic acids are compounds with a –COOH functional group. For the IUPAC nomenclature of monocarboxylic acids, identify the parent chain containing the –COOH carbon and replace the terminal -e of the corresponding alkane with the suffix -oic acid. Number the chain from the –COOH end and identify the substituents and their locant values. Lastly, assemble the name and indicate the stereochemistry. In the case of unsaturation, the parent name derives from the corresponding alkene or alkyne. To nomenclate dicarboxylic acids, select the parent chain that includes both the –COOH carbons and number from the end that gives the lowest locant to the substituents. Here, retain the terminal -e of the parent hydrocarbon and add the suffix -dioic acid. If the –COOH group is bonded to a ring, -carboxylic acid is suffixed to the parent name, and the numbering begins from the ring carbon bearing the –COOH group. In the presence of multiple –COOH groups, prefixes di- or tri- are used.