Question 1 Distilled water does not conduct electricity? Why?
Question 2 What substance can be added to distilled water in small amount to make it a good conductor of electricity. Why?
Question 3 Is it safe for the electrician to carry out electrical repairs outdoors during heavy downpour. Explain?
Question 4 Which is a better conductor of electricity : Drinking water or sea water? Explain?
Question 5 Does pure water conduct electricity? If not, what can we do to make it conducting?
Question 6 Rain water conduct electricity. Explain?
Question 7 The electrical conductivity of seawater is much more than that of drinking water? Why?
Question 8 Never operate an electric switch or touch any working electrical appliances with wet hands? Why?
(1) If we take some distilled water in a beaker and pass electricity through it, we will find that there is no deflection in the magnetic needle of compass. This shows that distilled water does not conduct electricity. Dissolve a pinch of common salt in distilled water. When salt is dissolved in distilled water we get salt solution. By passing current through it, we will find that the magnetic needle of compass shows deflection. Thus, distilled water becomes a good conductor of electricity on dissolving a little of salt in it.
Distilled water is a poor conductor of electricity because it does not contain any dissolved salts in it. Distilled water is pure water and it does not conduct electricity. We can make distilled water or pure water to conduct electricity in the following ways:
(i) We can dissolve some common salt in distilled water or pure water to make it a good conductor of electricity.
(ii) We can add a little of acid in distilled water or pure water to make it a good conductor of electricity.
(iii) We can add a little of base in distilled water.
(2) The water of taps, hand pumps, Wells and Ponds contains small amount of several salts which are naturally present in it and therefore conduct electricity.
We should never operate an electric switch or touch any working electrical appliances with wet hands because the tap water present on wet hands is a conductor of electricity due to which it may conduct electric current from the electric switch to our hand and give us an electric shock.
We should never handle an electrical appliance while standing barefooted on the wet floor.
In case of a fire, before the firemen use big water hoses to throw water on a burning house or building, they usually cut off the electricity supply of that area. Ordinary water is a conductor of electricity, so if the electricity supply is not cut off and fireman’s come in contact with with electric switches electric, wires and other electrical appliances they may get electrocuted.
Sea water contains a large amount of dissolved salts in it. Therefore the electrical conductivity of seawater is much more than that of drinking water. The deflection of magnetic needle of a compass is much more in the case of sea water than in the case of drinking water because due to the presence of a large amount of dissolved salts in it.
When rain water falls to the earth through the atmosphere, it dissolves an acidic gas carbon dioxide from the air and forms a weak acid called carbonic acid. The gases such as Sulphur dioxide and nitrogen oxide also form sulphuric acid and nitric acid. Due to the presence of small amount of acids in it rain water becomes a conductor of electricity .
It is not safe for electrician to carry out electrical repairs in the outdoor area during heavy downpour.