Hydroxide Tests (Activity 2)

• What are the ions tested?

  Cations (Metal-ions)
• What are the 5 metal ions tested?


  Aluminium, Calcium, Magnesium, Copper(II), Iron(II), Iron(III),
• Besides being metal ions, what type of ions are these?

  Positive
• What is the charge on the Aluminium Ion?

  3+
• What is the charge on the Calcium Ion?

  2+
• What is the charge on the Magnesium Ion?

  2+
• What is the charge on the Copper Ion?

  2+
• What is the charges of the Iron Ions tested?

  2+ and 3+
• So, what are the 6 metal ions?

  Aluminium, Al3+

  Calcium, Ca2+

  Magnesium, Mg2+

  Copper(II), Cu2+

  Iron(II), Fe2+

  Iron(III), Fe3+
• What precipitate does the Iron(II) ion form?

  Green
• What precipitate does the Iron(III) form?

  Brown
• What precipitate does the Copper(II) form?

  Pale blue
• What precipitate does the Aluminium(3+) Ion form?

  White
• What precipitate does the Calcium(2+) Ion form?

  White
• What precipitate does the Magnesium(2+) Ion form?

  White
• How do you distinguish aluminium from calcium and magnesium?

  Add excess sodium hydroxide solution. The Aluminium will dissolve and form a colourless solution whilst they will stay unchanged.
• How do you distinguish between calcium and magnesium?

  Using the flame test. Calcium will produce an orange-red colour.