carboxylic acids

Cards (12)

  • the C=O and O-H bonds in carboxylic acids are polar allowing carboxylic acids to form hydrogen bonds with water molecules
    • carboxylic acids with up to 4 carbon atoms are soluble in water
    • as the number of carbon atoms increases, the solubility decreases as the non polar carbon chain has a greater effect on the overall polarity of the molecule
  • dicarboxylic acids have two polar carboxyl groups to form hydrogen bonds
    they are solids at room temperature and dissolve readily in water
  • carboxylic acids are classified as weak acids. methanoic acid, HCOOH, is the simplest carboxylic acid containing only one carbon atom
  • when dissolved in water, carboxylic acids partially dissociate:
    HCOOH (aq) ⇌ H+ (aq) + HCOO- (aq)
  • aqueous solutions of carboxylic acids react with metals in a redox reaction to form hydrogen gas and the carboxylate salt
    in this reaction you would observe the metal disappearing and effervescence as hydrogen gas is evolved
  • propanoic acid with magnesium
    2CH3CH2COOH (aq) + Mg (s) -> (CH3CH2COO-)2Mg2+ (aq) + H2 (g)
  • reactions of carboxylic acids with metals
    with less reactive ones e.g Ca, Sr, Fe - no visible reaction as the metals are relatively unreactive
  • esterification is the reaction of an alcohol with a carboxylic acid to form an ester
    an alcohol is warmed with a carboxylic acid with a small amount of concentrated sulfuric acid, which acts as a catalyst
  • esters are sweet smelling liquids
  • the molecular formula for ethyl propanoate is C5H10O2
    it is a colourless liquid that smells like pineapples and is naturally produced in some fruits like kiwi fruit and strawberries
  • fats and oils are esters
    made from long chain carboxylic acids (fatty acids)
    glycerol - 1,2,3 - propantriol