Activity 3.8 Class 10 Science

In this activity, we will test the nature of oxides of metals and non-metals using litmus paper.

Nature of Oxides of Magnesium and Sulphur

Aim of the activity

To identify the nature of metal oxides and non-metal oxide

Materials Required

   1. Magnesium ribbon

   2. Sulphur powder

   3. Spirit lamp

   4. Red and blue litmus paper

   5. Water

   6. Test tube

   7. Watch glass

   8. Tongs

Procedure

We will perform this activity in two parts;

Part A: Burning of Magnesium

We hold a magnesium ribbon with tongs and burn over a flame. We collect the white ash (magnesium oxide) in a watch glass.

Now we dissolve the ash in water and test the solution with both red and blue litmus papers.

Part B: Burning of Sulphur

 

We take sulphur powder in a spoon and burn overt flame. Now we invert a test tube over the burning sulphur to collect sulphur dioxide gas.

 Now we add some water into the test tube and shake well. we test the solution with both red and blue litmus paper.

 Observation

Substance	Product formed	Litmus test	Nature of oxide
Magnesium	Magnesium oxide	Turns red litmus blue (no effect on blue litmus paper)	Basic
Sulphur	Sulphur dioxide	Turns blue litmus red (no effect on red litmus paper)	Acidic

 

Explanation

Magnesium is a metal and forms magnesium oxide when burned. Its solution in water turns red litmus into blue so it is basic in nature.

  2Mg + O₂ →2MgO

   MgO + H₂O → Mg (OH)₂ (Basic)

 

Sulphur is a non- metal and forms sulphur dioxide when burned. Its solution in water turns blue litmus into red so it is acidic in nature.

   S+ O₂ → SO₂

  SO₂   +H₂O → H₂SO₃(acidic)

 

Conclusion

This activity explains that metal oxides are basic in nature and oxides of non-metals are acidic in nature.

Frequently Asked Questions 

   1. Which acid is formed when SO₂ gas is dissolved in water?

Answer – Sulphurous acid H₂SO₃

   2. Name the base formed when MgO is dissolved in water.

Answer – Magnesium hydroxide

   3. Why does sulphur dioxide turn blue litmus red?

Answer – Sulphur dioxide is acidic in nature.