Chemical Tests

• Test for cations


  Add sodium hydroxide to metal ion solution
• results for cation

  Cu2+ - blue Cu(OH)2 copper hydroxide

  Fe2+ - green Fe(OH)2 iron (II) hydroxide

  Fe3+ - orange brown Fe(OH)2 iron (III) hydroxide
• cation test for ammonium

  add sodium hydroxide to ammonium solution

  damp red litmus turns blue
• Flame test


  get nichrome wire

  dip in HCL

  then into compound

  hold at cone of flame

  look at colour change
• Lithium flame colour


  red
• Sodium flame colour


  yellow
• Potassium flame colour


  lilac
• Calcium flame colour


  orange
• Copper flame colour


  blue green
• anion test


  add halide solution (Cl- Br- I-) to test tube

  add nitric acid

  add silver nitrate solution
• results for anion test

  Chloride: Cl- white ppt, AgCl

  Bromide: Br- cream ppt, AgBr

  Iodide: I- yellow ppt,
• Test for sulfate ions

  add sodium sulfate to test tube

  add dilute HCL

  add barium chloride solution
• test for carbonate ions

  add dilute HCl to sample of salt

  Fizzing indicates that a gas is given off

  Bubble through limewater to show carbon dioxide
• testing for the presence of water using anhydrous copper sulfate

  Anhydrous copper(II) sulfate is white

  dropped onto water it turns blue
• equation for anhydrous prac

  CuSO4(s) + 5H2O(l) -> CuSO4.5H20(s)