Hi.
A carboxylic acid is an organic compound that has a carboxyl group attached to an R-group. The general formula of a carboxylic acid is RCOOH, with R meaning to the alkyl group. Carboxylic acids are known  widely. Most common examples include the amino acids and fatty acids.
Carboxylic acids and their derivatives are used in the production of polymers, biopolymers, coatings, adhesives, and pharmaceutical drugs. They also can be used as solvents, food additives, antimicrobials, and flavorings.
Also the four carboxylic acid groups derived from alkanes are methanoic acid, ethanoic acid, propanoic acid and butanoic acid.