Alderhydes and ketones

• What two test for alderhydes are there?

  • Tollens
  • Fehlings
• What ions are present in Tollans regent, What positive test does it give?

  • [Ag(NH3)2]+
  • Positive for alderhydes
  • Silver mirror forms
• What ions are present in fehlings reagent, what positive test does it give?

  • Cu2+
  • Positive test for alderhydes
  • Blue -> brick red ppt forms
• What is is used to reduce both ketone and alderhydes?

  Sodium tetrahydroborate

  ( NaBH4 )
• Advantage of heating Ethanol under reflux to produce ethanoic acid

  • Is heated up for longer as it can evaporate and condense and be heated again. Which allows it to fully oxidised.
• Equation for the oxidation of Ethanol to ethanolic acid

  CH3CH2OH + H2O -> CH3COOH + 4H+ + 4e-
• Why dosnt the reduction of butanones product not have an effect on plane polarised light?

  • Planar carbonyl group, so equal chance of attack from either plane
  • 50:50 of each enantomer forms (racemic mixture)
  • So light rotates equally in opposite directions
• Equation of the reduction butanone

  CH3CH2COCH3 + 2[H] -> CH3CH2CH(OH)CH3