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SAI INTERNATIONAL SCHOOL

CLASS - VIII

Subject – CHEMISTRY

Chapter – CHEMICAL EFFECTS OF ELECTRIC CURRENT

TOPIC – Electrolysis, Simple circuit of electrolysis and Applications of the
Chemical Effects of Electric Current

LESSON NOTES

CHEMICAL EFFECTS OF ELECTRIC CURRENT:

 Electric current can bring about chemical changes, so it is said to have a chemical effect.

 When electric current passes through a conducting solution, it causes chemical
reactions. This is called Chemical Effects of Electric Current.

 Chemical effect of electric current may cause the following effects:
i. Formation of gas bubbles at the electrodes.

ii. Deposition of metals on the electrodes.

iii. Change in colour of the solution.
 The chemical effect produced by an electric current depends on the nature of conducting

solution, through which it is passed, and on the nature of electrodes used for passing the
electric current.

A. Demonstrating the Chemical Effect of Electric Current by passing current through

Acidified water:

 Take a plastic vessel. Drill two holes at its bottom and set rubber stoppers in these holes.
 Insert two carbon electrodes in these rubber stoppers and connect these electrodes to a

battery and a switch.
 Fill the vessel with water such that the electrodes are immersed. Add a few drops of dilute

sulphuric acid to the water in the vessel to make the water more conducting, i.e., acidified

water.
 Take two graduated test tubes filled with water and invert them over the two carbon

electrodes.
 Switch on the current.

 After sometime, you will observe the formation of bubbles at both the electrodes. These

bubbles displace water in the graduated tubes.

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