Evaluate Your Grasp
What do we observe when we let electric current flow through ordinary water in which some dilute
sulphuric acid has been added?
2. An electric current is made to flow through a strong solution of common salt. Which gas (es), if any,
is/are produced as a result of this current flow?
3. What do you understand by galvanised iron sheets?
4. An iron blade is 'electroplated using a solution of copper sulphate. What are you likely to observe?
5. Give one application of electroplating'.
Answers
QUESTIONS FROM TEXTBOOK
Q.1. Fill in the blanks:
(a) Most liquids that conduct electricity are solutions of __________ , __________ and __________.
(b) The passage of an electric current through a solution causes__________effect.
(c) If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the __________terminal of the battery.
(d) The process of depositing a layer of any desired metal on another metallic object, by means of electricity, is culled __________.
Ans. (a) acids, bases, salts
(b) chemical
(c) negative
(d) electroplating.
Q.2. When the free ends of a tester are dipped into a solution the magnetic needle shows deflection. Can you a plain the reason?
Ans. Yes, we can explain the reason. The magnetic needle will show deflection when circuit is complete.
The deflection ofmagnetic needle shows that the solution is a good conductor.
Q.3. Name three liquids, which when tested in the manner shown in Mg. 14.1 may cause the magnetic needle to defieet

Ans. Tap water, hydrochloric acid, sodium hydroxide.
Q.4. The bulb does not glow in the set up shown in Fig .14.2. List the possible reasons. Explain your answer.

Ans. The possible reasons may be:
(i) The connections of the circuit may b loose.
(ii) Bulb may b fused.
(iii) Cells may be used up.
(iv) The liquid may be poor conductor.
Q.5. A tester is used to check the conduction of electricity through two liquids, labelled A and B. It is found that the bulb of the tester glows brightly for liquid A while it glows very dimly for liquid B. You would conclude that:
(i) liquid A is a better conductor than liquid B.
(ii) liquid B is a better conductor than liquid A.
(iii) both liquids are equally conducting.
(iv) conducting properties of liquid cannot be compared in this r an.rr.er, Ans, We conclude that option (i) ‘liquid A is a better conductor than liquid B'