British chemist, William Nicholson had shown that if electrodes were immersed in water and a current was passed, bubbles of oxygen and hydrogen were produced. What do your understand by bubbles of hydrogen and oxygen?

A beaker contains an acidified copper sulphate solution. A copper plate and a carbon rod are kept in this copper sulphate solution. The copper plate is connected to the positive terminal of a battery whereas the carbon rod is connected to the negative terminal of the battery. What will you observe when an electric current is passed through this set-up for a considerable time?

State some of the characteristics of chemical changes brought about by the chemical effect of electric current.

Name three types of substances in which an electric current can produce a chemical effect.

Name any two applications of the chemical effect of electric current.

Does pure water conduct electricity? If not, what can we do to make it conducting?

Distilled water does not conduct electricity. What substances can be added to distilled .water in small amounts to make it a good conductor of electricity? Why?

Which effect of electric current is utilized for detecting the flow of current through a solution:

(a) when a torch bulb is used?

(b) when a compass is used?

Why is it dangerous to touch a working electrical appliance with wet hands?

Which of the two is a better conductor of electricity: drinking water (tap water) or sea water? Give reason for your answer.

What is the advantage of using LED in testing the electrical conductivity of liquids ?