Latest Updated : October 2023
Table of Contents
NCERT Solutions for Class 8 Science Chapter 11 Chemical Effects of Electric Current will assist you in scoring more marks. This includes the textbook and their solutions for Chemical Effects of Electric Current Chapter 11 of Class 8 Science, which is made in adherence to the updated syllabus 2023 released by CBSE.
Our solutions offer ample material to help students build a strong foundation and improve their understanding of the subject.
On this page, you will find all the NCERT Solutions for Class 8 Science Chapter 11 Chemical Effects of Electric Current which includes detailed exercise-based solutions. These NCERT Solutions for Class 8 Science are downloadable and easy to access. Our Science experts have meticulously developed these NCERT Solutions for Class 8 to support students in preparing for their Class 8 exams.
NCERT Solutions for Class 8 Science Chapter 11 Chemical Effects of Electric Current
Chemical Effects of Electric Current Class 8 Science NCERT Textbook Questions
Exercise Questions
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 _____________ effects.
(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 material by means of electricity is called ________________ .
Solution:
(a) Most liquids that conduct electricity are solutions of Acids , Bases and Salts.
(b) The passage of an electric current through a solution causes Chemical effects.
(c) If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the Negative terminal of the battery.
(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?
Solution:
The compass needle shows a deflection which means that current is flowing through the wire. The circuit becomes complete when the free ends of the tester are immersed inside the solution. So, the solution is conducting solution and that is the reason why a deflection is obtained in the compass needle.
3. Name three liquids, which when tested in the manner shown in Figure, may cause the magnetic needle to deflect.
Solution: Lemon Juice, Salt water, Vinegar, Tap water.
4. The bulb does not glow in the setup shown in Figure. List the possible reasons. Explain your answer.
Solution:
The possible reasons of the bulb not glowing may be as follows-
(i) Bulb may be fused.
(ii) Liquid may be a poor conductor of electricity or insulator.
(iii) Battery might be used up or exhausted.
(iv) Possibility of loose connection in the circuit.
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.
Solution: (i) liquid A is a better conductor than liquid B.
6. Does pure water conduct electricity? If not, what can we do to make it conducting?
Solution:
No, Pure water does not conduct electricity but we can make it conducting by adding impurities in it like salt, lemon juice etc.
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.
Solution:
The water hoses that the firemen use are not pure water. They contain some impurities and therefore are good conductors of electrcity. So, in order to protect themselves from electric shocks and to avoid any short circuit, they shut the main electrical supply for the 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?
Solution:
Drinking water is chemically tested and purified and does not contain any impurities. On the other hand, seawater contains a huge amount of impurities like salts and minerals hence the seawater is a better conductor of electricity and it produces a stronger magnetic field in the wire and hence deflects the compass needle more.
9. Is it safe for the electrician to carry out electrical repairs outdoors during heavy downpour? Explain.
Solution:
No, It’s not safe for the electrician to carry out electrical repairs outdoors during heavy downpour. Rain water contains many impurities which makes it a good conductor of electricity, in this case the electrician might get an electric shock or any short circuit might also occur.
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?
Solution:
Rainwater is pure and as good as distilled water but it undergoes contamination when it mixes with air pollutants like sulfur dioxide and nitrogen oxides, resulting in the formation of an acidic solution. This acidic solution becomes a conductor of electricity, leading to the deflection of a compass needle.
10. Prepare a list of objects around you that are electroplated.
Solution:
- Artificial jwellery are silver or gold plated.
- Different parts of cars and motor cycles are chromium plated to give them a shiny appearance.
- Metal door, Door handles are zinc plated.
- Tin cans, gas burner etc are also plated.
11. The process that you saw in Activity 11.7 is used for 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 transfered to the thin copper plate. Which electrode should be attached to the positive terminal of the battery and why?
Solution:
The thick rod made of impure copper should be connected to the positive terminal of the battery. This is because when an electric current is passed through the copper sulphate solution, it undergoes a process of dissociation into copper and sulphate ions. The positively charged free copper ions are attracted to the negative terminal of the battery, where they are deposited. On the other hand, the loss of copper from the solution is replenished by the impure copper rod, which is linked to the battery’s positive terminal.
Summary
On our platform ncertforclass8.com, you will get all the solutions expertly solved, ensuring utmost care and accuracy. The NCERT book for Class 8 Science is strictly followed while creating these solutions, adhering to the latest CBSE guidelines for NCERT Class 8 Science. We make sure to provide you quality content which will help you to understand the concepts in the best way possible. Also our solutions are completely free for you to access. You have the freedom to copy the NCERT Solutions for Class 8 Science, download them and even create PDF’s, making it convenient for your offline use.
If you are looking for free NCERT Solutions for Class 8 Science, you can bookmark our site ncertforclass8.com and you can download the free PDFs and also share them with your friends. We are currently working to provide you with the best solutions with the updated syllabus, so in case some things aren’t available at this point in time, they will be available soon. Also, feel free to reach out and ask your doubts or queries in the comments below. Happy Learning!
More CBSE Class 8 Study Materials-
- NCERT Solutions for Class 8 English
- NCERT Solutions for Class 8 Maths
- NCERT Solutions for Class 8 Social Science
- NCERT Solutions for Class 8 Science
- NCERT Solutions for Class 8 Sanskrit
- NCERT Solutions for Class 8 Hindi
- NCERT Solutions for Class 8 English Honeydew
- NCERT Solutions for Class 8 English It So Happened
- NCERT Solutions for Class 8 Hindi Bharat Ki Khoj
- NCERT Solutions for Class 8 Hindi Vasant Bhag 3
- NCERT Solutions for Class 8 Science
- NCERT Solutions for Class 8