Carboxylic acids
- Carboxylic acids is the name given to compounds containing the functional group carboxyl, -COOH
- The general formula of a carboxylic acid is CnH2n+1COOH which can be shortened to just RCOOH
Carboxylic acid functional group
Diagram of the general structure of a carboxylic acid. The R- represents a varying hydrocarbon chain
- The naming of a carboxylic acid follows the pattern alkan + oic acid
- The names and structure of the first four carboxylic acids are shown below
- Vinegar is an aqueous solution of ethanoic acid and contains about 5% of the acid by volume.
The structures and formulae of the first four carboxylic acids
- The formula for each carboxylic acid is:
- Methanoic acid- HCOOH
- Ethanoic acid- CH3COOH
- Propanoic acid- CH3CH2COOH
- Butanoic acid- CH3CH2CH2COOH
Examiner Tip
The carbon atom in the -COOH functional group is counted as part of the molecule and not just the functional group. E.g. CH3CH2CH2COOH has 4 carbon atoms so is called butanoic acid, not propanoic acid.
