Carboxylic Acids Quiz

Carboxylic Acids

• Form a homologous series, meaning they share a common general formula
• Differ from neighboring compounds by CH2 in their molecular formulae
• Exhibit a gradual variation in physical properties, such as boiling points
• Display similar chemical properties

Functional Group

• The functional group in carboxylic acids is the carboxyl group, -COOH
• Responsible for the typical reactions of carboxylic acids, which are weak acids
• Example of a carboxylic acid: ethanoic acid, commonly found in vinegar as a dilute solution

Properties of Carboxylic Acids

• Carboxylic acids react with metals to form a salt and hydrogen gas
• They react with carbonates to form a salt, water, and carbon dioxide gas
• They participate in neutralisation reactions to produce salt and water

Ethanoic Acid

• Also known as acetic acid
• Used to make vinegar, which contains around 5% by volume ethanoic acid

Salts Formed by Carboxylic Acids

• Salts formed by the reaction of carboxylic acids all end in -anoate
• Examples:
  • Methanoic acid forms methanoate salt
  • Ethanoic acid forms ethanoate salt
  • Propanoic acid forms propanoate salt
  • Butanoic acid forms butanoate salt

Reactions of Carboxylic Acids

Reaction with Metals

• Produces a metal salt and hydrogen gas
• Example: Ethanoic acid reaction with magnesium forms magnesium ethanoate and hydrogen gas
  • 2CH3COOH + Mg → (CH3COO)2Mg + H2

Neutralisation Reaction

• Produces a salt and water
• Example: Propanoic acid reaction with potassium hydroxide forms potassium propanoate and water
  • CH3CH2COOH + KOH → CH3CH2COOK + H2O

Reaction with Carbonates

• Produces a metal salt, water, and carbon dioxide gas
• Example: Butanoic acid reaction with potassium carbonate forms potassium butanoate, water, and carbon dioxide gas
  • 2CH3CH2CH2COOH + K2CO3 → 2CH3CH2CH2COOK + H2O + CO2