NCERT Solutions Class 8 Science Chapter 14 Chemical Effects Of Electric Current
NCERT Solutions Class 8 Science Chapter 14 Chemical Effects Of Electric Current: National Council of Educational Research and Training Class 8 Science Chapter 14 Solutions – Chemical Effects Of Electric Current. NCERT Solutions Class 8 Science Chapter 14 PDF Download.
NCERT Solutions Class 8 Science Chapter 14: Overview
Board | NCERT |
Class | 8 |
Subject | Science |
Chapter | 14 |
Chapter Name | Chemical Effects Of Electric Current |
Topic | Exercise Solutions |
NCERT Solutions Class 8 Science Chapter 14 – Chemical Effects Of Electric Current
CHAPTER: – 14
(CHEMICAL EFFECTS OF ELECTRIC CURRENT)
Exercise: –
1)Fill in the blanks.
(a) Most liquids that conduct electricity are solutions of,____acids, bases____ and ___salts____.
Explanation – (As the ions present in the solution of acids and base transfer electricity)
(b) The passage of an electric current through a solution cause ____chemical___ effects.
Explanation -(As the ions of that solution passes the electric current)
(c) If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the _____negative_____terminal of the battery.
Explanation – (As in this case copper became Cu (+2) and stuck to the negative terminal)
(d) The process of depositing a layer of any desired metal on another material by means of electricity is called _____electroplating_____.
2) When the free ends of a tester are dipped into a solution, the magnetic needle shows deflection. Can you explain the reason?
Ans: – When the free ends of a tester are dipped into a solution the magnetic needle shows deflection because of the electricity produces in the solution. Electricity always deflected by the current. As this electricity affect the deflectionof the magnetic needles, we see the deflection there.
3)Name three liquids, which when tested in the manner shown in Fig.14.9, may cause the magnetic needle to deflect.
Ans: – The liquids which causes the magnetic needle deflected is
- Hydrochloric acids.
- Tap water.
- NaCl solution.
4) The bulb does not glow in the setup shown in Fig.14.10. List the possible reasons. Explain your answer.
Ans: –
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 manner.
Ans: – Here option is (i) Liquid A is a better conductor than liquid B. Because of the better conductance of electricity, we see that bulb A glows more brightly.
6)Does pure water conduct electricity? If not, what can we do to make it conducting?
Ans: – The pure water doesn’t conduct electricity as there is no free electrons which carry the charge from one direction to the other. As this this pure water doesn’t produces electricity, we use some salt in the solution which helps in producing the electricity.
7)In case of a fire, before the firemen use the water hoses, they shut off the main electrical supply for the area. Explain why they do this.
Ans: – As we all know that the pure water doesn’t produces electricity and, in the hoses, there present an impure water which helps in producing electricity. So, the electrical supply should be shut off from the main supply as there is risks of electricity in that area.
8)A child staying in a coastal region tests the drinking water and also the seawater with his tester. He finds that the compass needle deflects more in the case of seawater. Can you explain the reason?
Ans:- As the seawater produces more electricity for the presence of more salts in it as compared to the drinking water where salts present is less amount. So, in seawater the needle deflects more because of the electricity is more in that.
9)Is it safe for the electrician to carry out electrical repairs outdoors during heavy downpour? Explain.
Ans: – There are remain a cause of electrocution when the electrical repairs in outside. The electricity will be felt by another object in that are because of the downpour. And as a result, it done in the inside to avoid the electrocution.
10) Paheli had heard that rainwater is as good as distilled water. So, she collected some rainwater in a clean glass tumbler and tested it using a tester. To her surprise she found that the compass needle showed deflection. What could be the reasons?
Ans: – Through the rain water various impurities came in contact with it and forms a conductor like situation in which the electricity transferred through it. So, when Paheli tested this water using the tester, she finds the compass needle deflect because of the electricity in it.
11)Prepare a list of objects around you that are electroplated.
Ans: – The object which are around us that are electroplated is
- Gas burner.
- Handle of different doors.
- Utensils
- Etc.