Testing for organic functional groups

Cards (4)

  • How do you test for an aldehyde ?
    Add tollens reagent - silver mirror
    add Fehlings solution - blue to red
  • how do you test for carboxylic acid
    Add solid sodium hydrogen carbonate
    effervescence
    CH3COOH + NaHCO3 —> CH3COONa + H2O + CO2
  • Testing for halogenoalkanes
    Add sodium hydroxide and bromobutane
    place is water Bath - increases rate of reaction
    add dilute nitric acid and silver nitrate
    cream precipitate forms
  • Practical considerations for test up tube reactions
    Use hot water Bath - dealing with flammable substances
    fume cupboard - produce toxic fumes
    anti-bumping granules - for test for aldehydes as we boil the mixture
    dilute solutions - diluting ethanoic acid makes it less flammable
    conditions need to be acidic (halogenoalknes) - neutralise OH- ions Ag+ + OH- —> AgOH(s)
    Alkaline conditions (fehlings solution) - allow ethanal to reduce Cu2+ to Cu1+