NCERT Solutions | Class 8 Science Chapter 14 | Chemical Effects of Electric Current

CBSE Solutions | Science Class 8

Check the below NCERT Solutions for Class 8 Science Chapter 14 Chemical Effects of Electric Current Pdf free download. NCERT Solutions Class 8 Science were prepared based on the latest exam pattern. We have Provided Chemical Effects of Electric Current Class 8 Science NCERT Solutions to help students understand the concept very well.

NCERT | Class 8 Science

NCERT Solutions Class 8 Science
Book:	National Council of Educational Research and Training (NCERT)
Board:	Central Board of Secondary Education (CBSE)
Class:	8th
Subject:	Science
Chapter:	14
Chapters Name:	Chemical Effects of Electric Current
Medium:	English

Chemical Effects of Electric Current | Class 8 Science | NCERT Books Solutions

You can refer to MCQ Questions for Class 8 Science Chapter 14 Chemical Effects of Electric Current to revise the concepts in the syllabus effectively and improve your chances of securing high marks in your board exams.

NCERT TEXTBOOK EXERCISES

cbse science class 8 book pdf, Question 1.

Fill in the blanks:

Most liquids that conduct electricity are solutions of……..,……………and …………..
The passage of an electric current through a solution causes…………..effects.
If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the………..terminal of the battery.
The process of depositing a layer of any desired metal on another material by means of electricity is called.………

ncert class 8 science Chapter 14 question answer, Answer :

acids, bases, salts
chemical
negative
electroplating.

cbse science class 8 Chapter 14, Question 2.

When the free ends of a tester are dipped into a solution, the magnetic needle shows deflection. Can you explain the reason?

cbse science class 8 solutions, Answer :

Yes, it is because the solution conducts electricity.

cbse science class 8 syllabus, Question 3.

Name three liquids, which when tested in the manner shown in Fig. 14.1, may cause the magnetic needle to deflect.
NCERT Solutions for Class 8 Science Chapter 14 Chemical Effects of Electric Current 1

NCERT Solutions for Class 8 Science Chapter 14 Chemical Effects of Electric Current 1

ncert class 8 science Chapter 14 question answer, Answer :

Tap water/sodium chloride solution, hydrochloric acid.

class 8 science Chapter 14, Question 4.

The bulb does not glow in the setup shown in Fig. 14.2. List the possible reasons. Explain your answer.

cbse science class 8 solutions, Answer :

List of possible reasons:

The liquid solution might be conducting electricity, but the current produced is too small so that the filament of the bulb does not get heated and the bulb does not glow.
Or, it is possible that the connections are loose.
Or, the bulb is fused.
Or, the cells are used up.

NCERT Class 8 Science book, Question 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.

ncert class 8 science Chapter 14 question answer, Answer :

If the bulb glows brightly with liquid A, it means that liquid A is a better conductor of electricity than B. So the answer will be (i).

NCERT Class 8 Science book PDF, Question 6.

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

cbse science class 8 solutions, Answer :

Pure water does not conduct electricity. It can be made conducting if acid, base, or salt is dissolved in it.

ncert class 8 science Chapter 14, Question 7.

In case of a fire, before the firemen use the water hoses, they shut off the main electrical supply of the area. Explain why they do this.

ncert class 8 science Chapter 14 question answer, Answer :

The water used in water hoses is not pure water and it conducts electricity. Firemen shut off the main electrical supply of the area because if the supply of electricity continues there may be a high risk of electrocution in the whole area due to water.

ncert class 8 science Chapter 14 notes, Question 8.

A child staying in a coastal region test 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?

cbse science class 8 solutions, Answer :

The impure water is the conductor of electricity. Seawater contains more impurity (salt) than drinking water. Therefore, seawater conducts more electricity than drinking water. That is why the compass needle deflects more in the case of seawater.

NCERT Science book Class 8 Solutions PDF free download, Question 9.

Is it safe for the electrician to carry out electrical repairs outdoors during heavy downpours? Explain.

ncert class 8 science Chapter 14 question answer, Answer :

It is not safe for the wireman to carry out electrical repairs outside during heavy downpours. Because during heavy downpour there is a high risk of electrocution.

ncert science class 8 book, Question 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?

cbse science class 8 solutions, Answer :

Rainwater is, of course, as good as distilled water but, when it passes through the atmosphere, it dissolves a lot of dust, dirt, and impurities and becomes conductive. So, when Paheli used a tester, its compass showed deflection.

ncert science class 8 Chapter 14, Question 11.

Prepare a list of objects around you that are electroplated.

ncert class 8 science Chapter 14 question answer, Answer :

Ornaments, wheel rims of vehicles, the handlebar of cycle and motorcycle, pots of one metal coated with other, bath taps, kitchen gas burner, the bottom of cooking utensils, handles of doors, tin cans, etc.

ncert science class 8 pdf free download, Question 12.

The process that you saw in Activity 14.7 (NCERT) is used for the purification of copper. A thin plate of pure copper and a thick rod of impure copper are used as electrodes. Copper from impure rod is sought to be transferred to the thin copper plate. Which electrode should be attached to the positive terminal of the battery and why?

cbse science class 8 solutions, Answer :

To perform such activity we have to arrange copper sulphate crystals and two copper plates each having a size around 10 cm long and 4 cm wide. Now take 250 mL distilled water in a clean and dry beaker. Dissolve two teaspoonfuls of copper sulphate crystals in it to obtain copper sulphate solution. (You may add few drops of dilute sulphuric acid to copper sulphate solution to make it more conducting). Clean each copper plate with sandpaper. Now rinse it with water. With the help of wires, connect one copper plate to each terminal of two cell batteries (Take care that the two plates do not touch each other).
NCERT Solutions for Class 8 Science Chapter 14 Chemical Effects of Electric Current 3

NCERT Solutions for Class 8 Science Chapter 14 Chemical Effects of Electric Current 3

Immerse two plates in copper sulphate solution as shown in Fig. 14.3. Allow the current to pass through for 5 to 7 minutes.

When an electric current is passed through the copper sulphate solution, copper sulphate dissociates into copper and sulphate. The free copper gets drawn to the plate connected to the negative terminal of the battery and thus gets deposited on that plate. Gradually, a layer of copper builds upon the plate.