Reactions of Carboxylic Acids (Edexcel IGCSE Chemistry)

• The carboxylic acids behave like other acids
• They react with metals to form a salt and hydrogen and with carbonates to form a salt, water and carbon dioxide gas
• They take part in neutralisation reactions to produce salt and water
• Ethanoic acid (also called acetic acid) is the acid used to make vinegar, which contains around 5% by volume ethanoic acid
• The salts formed by the reaction of carboxylic acids all end –anoate
• So methanoic acid forms a salt called methanoate, ethanoic a salt called ethanoate etc
• In the reaction with metals, a metal salt and hydrogen gas are produced
• For example in the reaction of ethanoic acid with magnesium, the salt magnesium ethanoate is formed:

2CH₃COOH + Mg → (CH₃COO)₂Mg + H₂

• In the reaction with hydroxides a salt and water are formed in a neutralisation reaction
• For example in reaction with potassium hydroxide the salt potassium propanoate is formed by reaction with propanoic acid:

CH₃CH₂COOH + KOH → CH₃CH₂COOK + H₂O

• In the reaction with carbonates a metal salt, water and carbon dioxide gas are produced
• For example in reaction with potassium carbonate the salt potassium butanoate is formed by reaction with butanoic acid:

2CH₃CH₂CH₂COOH + K₂CO₃ → 2CH₃CH₂CH₂COOK + H₂O + CO₂