Burning of Magnesium Ribbon

Aim

To observe the burning of magnesium ribbon and study the product formed.

Materials Required

Theory

When magnesium ribbon is heated over a flame, it catches fire and burns with a dazzling white flame. It reacts with oxygen present in the air to form magnesium oxide, which is a white powder. This is an example of a combination reaction and is highly exothermic.

Chemical Equation:
2Mg (s) + O₂ (g) → 2MgO (s) + Heat + Light

When magnesium oxide is dissolved in water, it forms magnesium hydroxide, which is basic in nature. It turns red litmus paper blue.

MgO (s) + H₂O (l) → Mg(OH)₂ (aq)

Procedure

1. Take a small piece of magnesium ribbon and clean it by rubbing it with sandpaper to remove the protective layer of magnesium oxide.
2. Hold the magnesium ribbon with a pair of tongs.
3. Ignite the Bunsen burner and hold the magnesium ribbon over the flame.
4. Observe the burning process carefully (do not look directly at the flame).
5. Collect the white ash formed in a watch glass.
6. Transfer the ash to a test tube, add a little water, and shake it well.
7. Test the resulting solution with red and blue litmus paper.

Precautions

1. Clean the magnesium ribbon with sandpaper before burning to remove the oxide layer.
2. Do not look directly at the dazzling white flame as it may harm your eyes. Wear safety goggles if possible.
3. Always hold the magnesium ribbon with a pair of tongs while burning.
4. Use a small piece of magnesium ribbon.