Carboxylic Acids (Edexcel IGCSE Chemistry): Revision Note
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 Tips and Tricks
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.
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