Test-tube reactions

• functional groups are determined by the observations made
• Test for alkenes


  Bromine water- only a few drops

  changes from brown to colourless in the presence of C=C
• Tests for alcohols

  1. acidified potassium dichromate (K2Cr2O7)

  • tertiary- the solution remains orange
  • primary or secondary- changes from orange to green as alcohols get oxidised

  2. Tollens' reagent

  • secondary (ketone)- no change
  • primary (aldehyde)- silver mirror
• Test for carboxylic acids

  Carbonates

  Form salt, CO2 and water- effervescence

  bubble gas produced through limewater- solution turns cloudy