List some examples of common carboxylic acids and esters and where you might find them.
A carboxylic acid is an organic compound that contains a carboxyl group (C(=O)OH). The general formula of a carboxylic acid is R–COOH, with R referring to the rest of the (possibly quite large) molecule.
Methanoic acid HC- COOH
Ethanoic acid H3C-C-COOH
Propanoic acid CH3-CH2-COOH
Esters are derived from carboxylic acids. A carboxylic acid contains the -COOH group, and in an ester the hydrogen in this group is replaced by a hydrocarbon group of some kind. This could be an alkyl group like methyl or ethyl, or one containing a benzene ring like phenyl.
All these acids and esters are available in laboratory and chemical shop.