testing for substances

• test for sulfate ions

  add HCl

  white precipitate or white solid forms
• test for alkenes

  add bromine water

  should change from orange to colourless
• group 7 in silver nitrate

  Cl: white precipitate

  Br: cream precipitate

  I: yellow precipitate
• group 7 in dilute aqueous ammonia

  Cl: soluble

  Br: insoluble

  I: insoluble
• group 7 in concentrated aqueous ammonia

  Cl: soluble

  Br: soluble

  I: insoluble