carboxylic acids

• Carboxylic acids functional group

  -COOH
• First four carboxylic acids and their molecular formula

  Methanoic acid HCOOH

  Ethanoic acid CH3COOH

  Propanoic acid C2H5COOH

  Butanoic acid C3H7COOH
• Carboxylic acid reactions with water

  • Carboxylic acids are soluble in water
  • When carboxylic acids are placed in water, they dissolve
  • A weakly acidic solution is formed
• carboxylic acid reactions with alcohol: esterification

  • Alcohols and carboxylic acids react to make esters in esterification reactions in the presence of an acid catalyst, usually concentrated sulfuric acid
  • Esters are compounds with the functional group R-COO-R
  • Esters are sweet smelling oily liquids used in food flavourings and perfumes
  • They are volatile, meaning they vapourise easily
  • Ethanoic acid will react with ethanol in the presence of concentrated sulfuric acid (catalyst) to form ethyl ethanoate:

  acid + alcohol $\Leftrightarrow$ ester + water
• carboxylic acid reactions with carbonate

  • In the reaction with carbonates a metal salt, water and carbon dioxide gas are produced
  • acid + metal $\rightarrow$ salt + hydrogen
• Why are carboxylic acids weak acids

  • Carboxylic acids dissolve in water, but they only partially ionise producing weakly acidic solutions with pH values of between 3 and 7
  • Carboxylic acids form an equilibrium with their ions, but most of the carboxylic acid molecules are undissociated