Carboxylic acids have many similarities to other acids. For example:
All salts formed by the reactions of carboxylic acids end in -anoate. The -COOH functional group determines how carboxylic acids react.
Carboxylic acids react with metals to form a salt and hydrogen gas.
For example, ethanoic acid reacts with magnesium to form a colourless solution of magnesium ethanoate, and hydrogen gas is given off.
Ethanoic acid + Magnesium → Magnesium ethanoate + Hydrogen gas
2CH3COOH + Mg → (CH3COO)2Mg + H2
Carboxylic acids react with hydroxides to produce a salt and water. This is a neutralisation reaction.
For example, when butanoic acid reacts with sodium hydroxide, it forms a colourless solution of sodium butanoate and water.
Butanoic acid + Sodium hydroxide → Sodium butanoate + Water
CH3CH2CH2COOH + NaOH → CH3CH2CH2COOHNa + H2O
Carboxylic acids react with carbonates to form a metal salt, water and carbon dioxide gas.
For example, propanoic acid reacts with sodium carbonate to form the salt potassium propanoate, water and carbon dioxide.
Propanoic acid + Sodium carbonate → Potassium propanoate + Water + Carbon dioxide
2CH3CH2COOH + Na2CO3 → 2CH3CH2COONa + H2O + CO2
In the presence of an acid catalyst, carboxylic acids react with alcohols to form esters and water. This reaction is called esterification. Esters are organic compounds with the functional group -COO-. They are often used as organic solvents, and as they have a fruity smell, they are also used in many foods and products (e.g. perfumes).
An example of esterification is when ethanoic acid reacts with ethanol to form the ester ethyl ethanoate.
Ethanol + Ethanoic acid → Ethyl ethanoate + Water