Which suffix indicates a carboxylic acid in nomenclature?

In the nomenclature of organic compounds, the suffix that designates a carboxylic acid is "-oic acid." Carboxylic acids are characterized by the presence of a carboxyl group (-COOH), and when naming these compounds, the "-oic acid" suffix is used to highlight this functional group.

For example, acetic acid is named from the parent hydrocarbon, ethane, by transforming the "ane" ending to "oic acid." This indicates that the compound is not just an alkane but a carboxylic acid due to the presence of the carboxyl group. This naming convention is critical because it allows chemists to readily identify the functional group’s type and its reactivity based on the suffix of the compound.

The other options represent different functional groups or aspects of organic nomenclature. The suffix "-ol" indicates alcohols, which contain hydroxyl groups (-OH). The suffix "-al" designates aldehydes, which contain a carbonyl group (C=O) at the end of a carbon chain. Finally, "-ane" is used for alkanes, indicating saturated hydrocarbons without functional groups. Thus, using "-oic acid" is specifically correct for identifying the