Question

Write an activity to show dissociate of water into hydrogen and oxygen. 

(OR) 

Write an activity showing decomposition of a compound in the presence of electricity. 

(OR)

Draw a neat diagram representing electrolysis of water. How do you prove that water contains hydrogen and oxygen in the ratio of 2 : 1? 

(OR)

Explain electrolysis of water. 

(OR) 

What are the materials required for the experiment to show the chemical decomposition of water ? Write the procedure of the experiment. Name the products which we get in this reaction. 

(OR) 

Draw a neat diagram showing the electrolytic decomposition reaction of water. Write the balanced chemical equation of the above reaction.

Answer 1

1. Take a plastic mug. 

2. Drill two holes at its base. 

3. Fit two ‘one holed rubber stoppers’ in these holes. 

4. Insert two graphite electrodes in these rubber stoppers. 

5. Connect the electrodes to 9V battery. 

6. Fill the mug with water, so that the electrodes are immersed. 

7. Add few drops of dilute sulphuric acid to water. 

8. Take two test tubes filled with water and invert them over the two graphite electrodes. 

9. Switch on the current and leave the apparatus undisturbed for sometime. 

10. We will notice that the liberation of gas bubbles at both the electrodes. 

11. These bubbles displace the water in the test tubes. 

12. We also observe that the volume of gas collected in the both test tubes is different. 

13. Once the test tubes are filled with gases take them out carefully. 

14. Test both the gases separately by bringing a burning candle near the mouth of each test tube.

15. The gas which occupies high volume makes to burn with blue flame and put off candle flame with ‘puff sound is hydrogen gas. 

16. The gas which occupies low volume and makes to burn candle brightly is oxygen gas. 

17. In the above activity on passing the electricity, water dissociates to hydrogen and oxygen gases. This is called electrolytic composition reaction.