Tests

• alkene: shake with bromine water


  orange -> colourless
• all alcohols: metallic Na


  effervescence
• 1, 2, 3 alcohols: acidified potassium dichromate


  1,2 - orange to green

  3 - stays orange
• aldehyde

  • warm with fehlings solution [cu2+] -- blue to red
  • warm with tollens reagent -- silver ppt (mirror)
• carboxylic acid: add carbonate


  CO2 released - turns limewater cloudy
• sulphate ions, SO4^2-

  • acidify with dilute HCl
  • add BaCl
  • white ppt of BaSO4
• carbonate ions, CO3^2-

  • dilute HCl

  effervescence - turns limewater cloudy
• hydroxide ions, OH-

  damp red litmus paper

  • turns from red to blue
• ammonium ion, NH4+

  add NaOH

  heat

  hold damp red litmus paper to test tube

  • paper turns from red to blue