Carboxylic acids

Carboxylic acids are made from reacting an alcohol with an oxidising agent.

Carboxylic acids are a homologous series, meaning they all have the same functional group.

Dissolving carboxylic acids in water

In water, carboxylic acids are weak acids.

Let’s use ethanoic acid.

Ethanoic acid ionises to produce the ethanoate ion and H+. This is a reversible reaction, meaning the ethanoate ion and H+ can recombine to form ethanoic acid.

Because carboxylic acids only partially ionise in aqueous solution, they are weak acids. That means they have a higher PH than strong acids.

Reaction with metal carbonate

Carboxylic acid + sodium carbonates makes salt + carbon dioxide + water

E.g.

Ethanoic acid + sodium carbonate makes sodium ethanoate + carbon dioxide + water

Propanoic acid + potassium carbonate makes potassium propanoate + carbon dioxide + water

Reacting with alcohols

Carboxylic acid + alcohol makes ester + water

E.g.

Ethanoic acid + ethanol makes ethyl ethanoate + water

This reaction requires sulfuric acid as a catalyst.

This reaction is reversible.