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Organic Chemistry

Topic 5 of 7

Carboxylic acids: recognise -COOH

A functional group gives a family its characteristic chemistry.

O-Level 5086 / 5088 (2026) / SEC G3 K326 / K328 (2027)

Carboxylic acids: recognise -COOH

A functional group gives a family its characteristic chemistry.

Carboxylic acids contain the -COOH group, also written -CO2H. This includes a C=O bond and an O-H bond on the same carbon. Ethanoic acid is CH3COOH; it can form when ethanol is oxidised by oxygen in air or by warm acidified potassium manganate(VII). The carbon skeleton is retained in this conversion.

Check your understandingWhat distinguishes the functional group in ethanol from the one in ethanoic acid?Think it through, then reveal the answer
Ethanol contains an alcohol -OH attached to a carbon chain. Ethanoic acid contains -C(=O)-OH: its -OH is part of the carboxyl group. Recognise the whole group, not just the letters OH.