Carboxylic acids are a homologous series of compounds. Each member differs from the next by one -CH2 group in the molecular formulae. All carboxylic acids share similar chemical properties, but there is a gradual variation in their physical properties. For example:
One easy way to identify a carboxylic acid is through the ‘-oic acid’ ending in the name. The functional group responsible for the chemical behaviour of carboxylic acids is the carboxyl group, represented as ‘-COOH’.
The general formula for carboxylic acids is:
In terms of the carboxylic acid structure – their molecular formula, structural formula and ball-and-stick model can be seen below:
The molecular formula, structural formula and ball-and-stick model of the first four carboxylic acids can be seen in the table below:
|Carboxylic acid||No. of carbon atoms||Formula||Structural formula||Ball + stick diagram|