qualitative analysis

• Aluminium ion (Al3+) produces white precipitate when sodium hydroxide is added and is soluble in excess
• Aluminium ion (Al3+) produces white precipitate when aqueous ammonia is added and is insoluble in excess.
• Zinc ion (Zn2+) produces white precipitate when sodium hydroxide is added and is soluble in excess.
• Zinc ion (Zn2+) produces white precipitate when aqueous ammonia is added and is soluble in excess.
• Calcium ion (Ca2+) produces white precipitate when sodium hydroxide is added and is insoluble in excess.
• Ammonium ion (NH4+) turns damp red litmus paper blue when sodium hydroxide is added.
• Copper ion (Cu2+) produces light blue precipitate when sodium hydroxide is added and is insoluble in excess.
• Copper ion (Cu2+) produces light blue precipitate when aqueous ammonia is added and is soluble in excess.
• iron (II) ion (Fe2+) produces green precipitate when sodium hydroxide is added and is insoluble in excess. It turns brown on standing
• Iron (III) ion (Fe3+) produces red-brown precipitate when sodium hydroxide is added and is insoluble in excess.
• Iron (III) ion (Fe3+) produces red-brown precipitate when aqueous ammonia is added and is insoluble in excess.
• carbonate ion, CO3^2-

  test:

  1. Add dilute acid
  2. Bubble the gas given off into limewater

  observation:

  bubbles observed

  gas forms white percipitate of CaCo3 with limewater

  carbon dioxide is produced
• Chloride ion, Cl-

  test:

  1. Add dilute nitric acid
  2. add aqueous silver nitrate

  observation:

  white precipitate of AgCl is formed
• Sulfate ion, SO4^2-

  test:

  1. Add dilute nitric acid
  2. add aqueous barium nitrate

  observation:

  white precipitate of BaSO4 is formed
• Nitrate ion, NO3-

  test:

  1. Add dilute sodium hydroxide
  2. add aluminium foil
  3. warm mixture carefully
  4. test gas given off with damp red litmus paper

  observation:

  bubbles observed

  gas given off turns red litmus paper blue

  ammonia gas is produced