Which of the following is the first member of the carboxylic acids homologous series?

The first member of the carboxylic acids homologous series is methanoic acid. Carboxylic acids are organic compounds that contain a carboxyl group (-COOH), and they can be classified based on the number of carbon atoms present.

Methanoic acid, also known as formic acid, has one carbon atom in its structure, making it the simplest and therefore the first member of the series. As the chain of carbon atoms increases, so do the members of the series: ethanoic acid (two carbons), propanoic acid (three carbons), and butanoic acid (four carbons) follow in this sequence.

Each subsequent member of this series increases in size by one carbon atom and has a corresponding increase in molecular weight and complexity, with each compound still retaining the characteristic carboxylic acid functional group. Methanoic acid serves as the foundational building block for others in the series, solidifying its position as the first member.