Activity 1.1- Burning of magnesium ribbon

Activity 1.1- Burning of magnesium ribbon

Burning of a Magnesium Ribbon in Air

Materials Required:

• Magnesium ribbon (clean and about 3–5 cm long)
• Tongs
• Bunsen burner or spirit lamp
• Watch-glass

Activity 1.1- Burning of magnesium ribbon

Procedure:

1. Cleaning the Magnesium Ribbon:
   • Magnesium ribbon often has a layer of oxide on its surface.
   • Rub the ribbon gently with sandpaper to remove this layer. This ensures the ribbon burns easily and completely.
2. Holding the Ribbon:
   • Use tongs to hold one end of the ribbon.
   • Keep your eyes protected as the burning magnesium emits intense white light.
3. Burning the Ribbon:
   • Bring the free end of the ribbon near the flame.
   • Once it ignites, it burns with a brilliant white flame.
   • The chemical reaction taking place is:

• Magnesium (Mg) reacts with oxygen (O₂) in the air to form magnesium oxide (MgO), a white powder.

1. Collection of Magnesium Oxide:
   • Hold a clean watch-glass underneath the burning ribbon (without touching the flame directly).
   • The white ash formed (magnesium oxide) falls and collects on the watch-glass.

Observation:

• The magnesium burns with a dazzling white flame.
• A white powdery ash (magnesium oxide) is formed and settles on the watch-glass.

Conclusion:

• Magnesium reacts with oxygen to form magnesium oxide.
• This experiment demonstrates the reactivity of metals, combination reactions, and the importance of removing oxide layers from reactive metals for complete combustion.

FAQs

Q1. Why is the magnesium ribbon cleaned before burning?

Ans:
Magnesium ribbon is cleaned to remove the protective oxide layer (MgO) that forms on its surface when exposed to air. This oxide layer prevents proper burning, so it is removed by rubbing with sandpaper to allow a smooth and complete combustion.

Q2. What do you observe when magnesium burns in air?

Ans:
Magnesium burns with a bright white flame, and a white powdery substance (magnesium oxide) is formed.

Q3. What is the chemical reaction involved in the burning of magnesium?

Ans: 2Mg (s) + O₂(g)→2MgO 

This is a combination and exothermic reaction.

Q4. What is the white powder formed after burning magnesium?

Ans:
The white powder is magnesium oxide (MgO), a basic oxide.

Q5. Why should you not look directly at the burning magnesium?

Ans:
The light produced is very intense and can damage your eyes. It is advised to wear safety goggles or avoid looking directly at the flame.

Q6. Is magnesium oxide acidic or basic in nature?

Ans:
Magnesium oxide is basic. It reacts with acids to form salt and water.

Q7. What type of reaction is the burning of magnesium?

Ans:
It is a combination reaction (magnesium + oxygen → magnesium oxide) and also an exothermic reaction (heat and light are released).

Q8. Can magnesium burn in nitrogen?

Ans:
Yes, magnesium can burn in nitrogen at high temperatures to form magnesium nitride (Mg₃N₂), but it mainly reacts with oxygen in air.

Q9. Why is a watch-glass used in this experiment?

Ans:
The watch-glass is used to collect the white ash (magnesium oxide) formed during the burning.

Q10. What precautions should be taken during this experiment?

Ans:

• Clean the ribbon before burning.
• Hold it with tongs, not bare hands.
• Do not look directly at the flame.
• Perform the experiment in a well-ventilated area or under a fume hood.