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NCERT Solutions for Class 8 Science Chapter 11 Chemical Effects Of Electric Current

NCERT Solutions for Class 8 Science Chapter 11 Chemical Effects Of Electric Current

Edited By Vishal kumar | Updated on Jun 26, 2025 01:03 PM IST

Want to know how electric current can even split water? Class 8 Science Chapter 11 Chemical Effects of Electric Current introduces students to fundamental concepts of electricity and its chemical effects, which are vital in understanding more complex topics like current electricity, electrochemistry, and more. The NCERT solutions of class 8 science by Careers360 professionals make you understand these awesome concepts easily and understand their practical uses.

NCERT Solutions of Chemical Effects of Electric Current includes 12 questions on the different activities given in the chapter. Here you will find detailed and easy-to-understand solutions that help prepare for exams. You can view the topics covered in this chapter at a glance, as well as the important concepts learnt. Also, find the guide to learning the chapter and the crucial points to remember under the approach to solve NCERT questions. Chapter 11 of the NCERT Solutions Class 8 plays a pivotal role in laying a strong foundation for higher classes, particularly in the field of physics and chemistry. Students can also find the links to the NCERT solutions of other chapters of class 8 below.

This Story also Contains
  1. NCERT Solutions for Class 8 Science Chapter 11: Download PDF
  2. NCERT Solutions Chemical Effects of Electric Current Class 8: Exercise Questions
  3. NCERT Solutions for Class 8 Science Chapter 11: Topics
  4. NCERT Solutions for Class 8 Science Chapter 11: Important Concepts
  5. Approach to solve the NCERT Class 8 Science Chapter 11 Questions
NCERT Solutions for Class 8 Science Chapter 11 Chemical Effects Of Electric Current
NCERT Solutions for Class 8 Science Chapter 11 Chemical Effects Of Electric Current

NCERT Solutions for Class 8 Science Chapter 11: Download PDF

Download the free PDF of NCERT Solutions for Class 8 Science Chapter 11 – Chemical Effects of Electric Current. It is suitable for offline access and last-minute revision.

Download PDF

NCERT Solutions Chemical Effects of Electric Current Class 8: Exercise Questions

Q1. 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_____________ .

Answer:

(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.

Q2. When the free ends of a tester are dipped into a solution, the magnetic needle shows deflection. Can you explain the reason?

Answer:

The magnetic needle shows deflection and therefore current must be flowing through the circuit. The circuit is complete and therefore the solution is electrically conducting due to the presence of charged particles called ions.

Q3 . Name three liquids, which when tested in the manner shown in Fig.11.9, may cause the magnetic needle to deflect.

Testing Of current through a solution

Answer:

Three liquids which may cause the magnetic needle to deflect when tested in the manner shown in Fig 10.9 are lemon juice, salt solution and vinegar.

Q4. The bulb does not glow in the setup shown in Fig.11.10 List the possible reasons. Explain your answer.

Electric circuit in chemical effect of electric current

Answer:

The bulb might not glow due to the following reasons:

(a) The liquid might not be a conductor of electricity.

(b) The current might be very weak and not sufficient enough to light the bulb, this could happen due to the battery not being charged or because of the circuit being poorly conducting.

Q5. 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.

Answer:

(i) liquid A is a better conductor than liquid B.

The brightness of the bulb depends on the current flowing through it which in turn depends on the conductivity of the liquid. Since the brightness of the bulb is more in case of liquid A we conclude liquid A is a better conductor than liquid B.

Q6. Does pure water conduct electricity? If not, what can we do to make it conducting?

Answer:

No, pure water does not conduct electricity because of the absence of charged particles known as ions which facilitate conduction of electricity. To make it conducting we can add salt, acid or base to the water.

Q7. 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.

Answer:

As we know water is a conductor of electricity, the poured water may come in contact with some electrical appliance or electrical cable causing the current to reach the firemen and harm them. Thus to avoid this the main electrical supply for the area is shut down before the firemen use the water hoses.

Q8. 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?

Answer:

Seawater is salty and as we know salt imparts the property of electrical conduction to water, it will be more conducting than drinking water which has a lesser amount of dissolved salt than seawater. Due to higher electrical conductivity, the deflection of the needle is more in the case of seawater.

Q9. Is it safe for the electrician to carry out electrical repairs outdoors during heavy downpour? Explain.

Answer:

No, it is not safe for the electrician to carry out electrical repairs outdoors during a heavy downpour as rainwater contains dissolved salts which makes rainwater a good conductor of electricity and due to this the electrician might get an electric shock while working outdoors during a heavy downpour.

Q10. 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?

Answer:

The reason behind the needle showing deflection in case of rainwater is the fact that rainwater has dissolved salts in it which makes it a good conductor of electricity whereas distilled water is completely devoid of any salts and does not conduct electricity.

Q11. Prepare a list of objects around you that are electroplated.

Answer:

List of objects which are electroplated around us:

(i) Gold is electroplated on ornaments.

(ii) Zinc is electroplated on pipes and machinery.

(iii) Chromium is electroplated on parts of vehicles.

(iv) Tin is used to coat metal containers for food.

Q12. The process that you saw in Activity 10.7 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 transferred to the thin copper plate. Which electrode should be attached to the positive terminal of the battery and why?

Answer:

Copper ions carry a positive charge and would be attracted towards the negative terminal. Since we want to transfer copper from the thick impure copper rod to the thin copper strip, the thick copper rod should be connected to the positive terminal of the battery and consequently the thin copper strip to the negative terminal of the battery.

NCERT Solutions for Class 8 Science Chapter 11: Topics

Topics for class 8 chemical effects of electric current NCERT solutions are listed below:

  • Do Liquids Conduct Electricity?
  • Chemical Effects of Electric Current
  • Electroplating
Background wave

NCERT Solutions for Class 8 Science Chapter 11: Important Concepts

Electric Current:

Flow of electrons through a conductor.

Good Conductors:

Materials like copper and aluminium that allow current to pass through.

Insulators:

Materials like rubber and plastic that do not allow current to pass through.

LED Glowing Test:

A simple method to test if a liquid conducts electricity.

Compass Needle Test:

A test utilising the magnetic effect of current by checking if a compass needle is deflected.

Electrolyte:

A liquid that conducts electricity and undergoes chemical changes.

Electroplating:

A process where a metal is coated on another material using electric current.

Chemical Effects of Electric Current:

  • Change in colour of the solution

  • Formation of gas bubbles

  • Deposition of metal on electrodes

  • Heating effect in some cases

  • Electroplating of metals

Approach to solve the NCERT Class 8 Science Chapter 11 Questions

Understanding electricity and the properties of conductors and insulators is essential for this chapter. This includes testing for the flow of current, using its magnetic effect to see deflection in a compass needle or by connecting a light source like a bulb or an LED to the circuit. It is important to learn what makes liquids conduct electricity and the requirements to do so. Finally, we understand the chemical reactions that can occur when current is passing and its practical application, such as electroplating. It is important to learn about different materials and liquids, and note the effect of electricity on them.

NCERT Chapter-Wise Solutions For Class 8th Science

The chapter-wise NCERT solutions for all the science chapters are listed here along with their links:

NCERT Solutions For Class 8: Subject-Wise

Also Check NCERT Books and NCERT Syllabus here:

Frequently Asked Questions (FAQs)

1. What is electroplating?

Electroplating is the chemical process of covering an object with a thin layer of metal by electrochemical disposition

2. What are the topics covered in NCERT Class 8 Science chapter 11 ?

Here are the topics covered in NCERT Class 8 Science chapter 11

  •   Do Liquids Conduct Electricity?  
  •   Chemical Effects of Electric Current  
  •   Electroplating  
3. How chapter 11 class 8 science is important for exam?

Chapter 11 "Chemical Effects of Electric Current" is important for exams as it covers the concepts of electroplating, electrolysis, and how electricity can bring about chemical changes in substances. A thorough understanding of this chapter is essential for students interested in pursuing higher studies in science and for performing well in competitive exams.

4. What is an electrolyte?

Electrolytes are liquids that can conduct electricity. These are usually solutions of acids, bases and salts. 

5. What are some methods to test the conduction of electricity?

To test if electricity is flowing, you can use the LED glowing test or the compass needle test.

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Option 1)

0.34\; J

Option 2)

0.16\; J

Option 3)

1.00\; J

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0.67\; J

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2.45×10−3 kg

Option 2)

 6.45×10−3 kg

Option 3)

 9.89×10−3 kg

Option 4)

12.89×10−3 kg

 

An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range

Option 1)

2,000 \; J - 5,000\; J

Option 2)

200 \, \, J - 500 \, \, J

Option 3)

2\times 10^{5}J-3\times 10^{5}J

Option 4)

20,000 \, \, J - 50,000 \, \, J

A particle is projected at 600   to the horizontal with a kinetic energy K. The kinetic energy at the highest point

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K/2\,

Option 2)

\; K\;

Option 3)

zero\;

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K/4

In the reaction,

2Al_{(s)}+6HCL_{(aq)}\rightarrow 2Al^{3+}\, _{(aq)}+6Cl^{-}\, _{(aq)}+3H_{2(g)}

Option 1)

11.2\, L\, H_{2(g)}  at STP  is produced for every mole HCL_{(aq)}  consumed

Option 2)

6L\, HCl_{(aq)}  is consumed for ever 3L\, H_{2(g)}      produced

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33.6 L\, H_{2(g)} is produced regardless of temperature and pressure for every mole Al that reacts

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67.2\, L\, H_{2(g)} at STP is produced for every mole Al that reacts .

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Option 1)

0.02

Option 2)

3.125 × 10-2

Option 3)

1.25 × 10-2

Option 4)

2.5 × 10-2

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Option 1)

decrease twice

Option 2)

increase two fold

Option 3)

remain unchanged

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be a function of the molecular mass of the substance.

With increase of temperature, which of these changes?

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Molality

Option 2)

Weight fraction of solute

Option 3)

Fraction of solute present in water

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Mole fraction.

Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is

Option 1)

twice that in 60 g carbon

Option 2)

6.023 × 1022

Option 3)

half that in 8 g He

Option 4)

558.5 × 6.023 × 1023

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Option 1)

less than 3

Option 2)

more than 3 but less than 6

Option 3)

more than 6 but less than 9

Option 4)

more than 9

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