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

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

Edited By Vishal kumar | Updated on Sep 15, 2023 01:18 PM IST

NCERT Solutions Class 8 Science Chapter 14 – Access and Download Free PDF

NCERT Solutions for Class 8 Science Chapter 14 Chemical Effects of Electric Current serves as a vital tool for achieving high marks in exams. These chemical effects of electric current class 8 solutions not only aid in scoring well but also lay the foundation for more advanced topics like current electricity. Understanding the chemical effects of electric current through NCERT Solutions is essential as it has practical applications in various fields. Therefore, mastering this chapter not only ensures success in exams but also enhances students' knowledge of fundamental scientific principles.

The experts at Careers360 have created a comprehensive solution for chemical effects of electric current class 8. The solution is presented in simple language with step-by-step explanations for all twelve questions. Students can easily download the PDF version of the solution and use it at their convenience for exam preparation. With this class 8 chapter 14 science resource, students can enhance their understanding of the topic and improve their performance in exams.

class 8 science chapter 14 solution is part of NCERT Solutions for class 8. Often your parents ask you not to touch dysfunctional electrical appliances with wet hands. Or while turning on or off electrical appliances, they ask you to wear slippers. All these precautions are taken just to avoid the effects of electric current.

In CBSE NCERT Solutions for Class 8 Science chapter 14 Chemical Effects of Electric Current, you will get to learn what is electric current, how electricity can be used in chemical reactions, what are the applications of the chemical effect of current etc. Chemical effects of electric current class 8 ncert solutions help students to understand the chapter well. Having solutions of NCERT for Class 8 Science chapter 14 Chemical Effects of Electric Current ready in hand will be beneficial for exam preparation. Try yourself to do the exercise questions before taking the help of NCERT solutions for Class 8 Science Chapter 14 Chemical Effects of Electric Current.

** This chapter has been renumbered as Chapter 10 in accordance with the CBSE Syllabus 2023–24.

Free download class 8 chemical effects of electric current ncert solutions PDF for CBSE exam.

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

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NCERT Solutions for Class 8 Science Chapter 14 Chemical Effects of Electric Current: Solved 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.14.9, may cause the magnetic needle to deflect.

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Answer:

Three liquids which may cause the magnetic needle to deflect when tested in the manner shown in Fig 14.9 are lemon juice, salt solution and vinegar.

Q4. The bulb does not glow in the setup shown in Fig.14.10. List the possible reasons. Explain your answer.

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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 14.7 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.

Class 8 Science chapter 14 questions answer play a pivotal role in laying a strong foundation for higher classes, particularly in the field of physics and chemistry. This chapter 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. By mastering this class 8 science ch 14 question answer, students gain a solid understanding of these concepts, which proves invaluable as they progress to higher classes and delve deeper into the world of science and technology

NCERT Solutions For Class 8 Science- Chapter-Wise

Chemical Effects of Electric Current Class 8 Questions and Answers: Important Formulas and Points

  • Electric Current: Electric current is the flow of electric charge through a conductor. It is measured in amperes (A).

  • Conductors and Insulators: Conductors are materials that allow an electric current to pass through easily (e.g., metals like copper and aluminium). Insulators are materials that do not allow electric current to pass through easily (e.g., rubber, plastic, and wood).

  • Chemical Effects of Electric Current: When electric current passes through certain substances, it can lead to chemical changes in those substances.

  • Electrolytes: Substances that conduct electricity when dissolved in water are called electrolytes. Examples include acids, bases, and salts.

  • Electrodes: Conducting rods or plates used to immerse in electrolytes to pass an electric current are called electrodes. There are two types: the anode (positive electrode) and the cathode (negative electrode).

  • Electrolysis: Electrolysis is the process of using electricity to bring about a chemical change in an electrolyte. It involves the migration of ions to the electrodes.

Formula for calculating the mass of an element deposited by an electric current

Mass deposited = (current × time) / (constant of the element)

Charge (Q)

Q = I × t

Where: Q is the charge in coulombs (C), I is the current in amperes (A) and t is the time in seconds (s).

Voltage (V)

V = I × R

Where: V is the voltage in volts (V), I is the current in amperes (A) and R is the resistance in ohms (Ω).

Chemical Effects of Electric Current Class 8 NCERT Science: 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

NCERT Solutions for Class 8 Science Chapter 14 Chemical effects of electric current - Points to remember:

Some of the important points of Science Chapter 14 class 8 that you will learn with the help of NCERT solutions for Class 8 Science Chapter 14 Chemical Effects of Electric Current are as follows:

  • Liquids that can conduct electricity. For example tap water, salt solutions, acid solution, base solution, etc. This is due to the presence of minerals in the liquid. In distilled water minerals are absent, so it does not allow passage of current
  • When we pass electricity through a chemical solution certain reactions take place. These reactions are collectively called the chemical effects of electric current.
  • The chemical effects of electric current are used for various applications. E.g electroplating.
  • Electroplating is the deposition of a layer of desired metal onto another material via electricity.

Key Features of Class 8 Science Chapter 14 question answers

  1. Comprehensive Coverage: These chemical effects of electric current class 8 solutions cover all the important topics related to "Chemical Effects of Electric Current" in the Class 8 curriculum.

  2. Concept Clarity: The chemical effects of electric current class 8 ncert solutions provide clear and concise explanations to ensure students understand the concepts thoroughly.

  3. Variety of Questions: The questions cover a range of topics, including the effects of electric current on substances, electrolysis, and practical applications.

  4. Practice Questions: Multiple practice questions of science chapter 14 class 8 help students reinforce their understanding and problem-solving skills.

  5. Visual Aids: Diagrams and illustrations are included where relevant to enhance understanding.

  6. Free Access: These class 8 science chapter 14 ncert solutions are freely accessible, making them available to all students for study and revision.

NCERT Solutions For Class 8: Subject-Wise

Also Check NCERT Books and NCERT Syllabus here:

Frequently Asked Question (FAQs)

1. How Many Questions covered in ncert solutions for class 8 science chapter 14

NCERT solutions for class 8 science chapter 14 "Chemical Effects of Electric Current" cover a total of 12 questions



2. What is electroplating?

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

3. What are the topics covered in NCERT Class 8 Science chapter 14 ?

Here are the topics covered in NCERT Class 8 Science chapter 14

  •   Do Liquids Conduct Electricity?  
  •   Chemical Effects of Electric Current  
  •   Electroplating  
4. How chapter 14 class 8 science is important for exam

Chapter 14 "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.

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A block of mass 0.50 kg is moving with a speed of 2.00 ms-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is

Option 1)

0.34\; J

Option 2)

0.16\; J

Option 3)

1.00\; J

Option 4)

0.67\; J

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times.  Assume that the potential energy lost each time he lowers the mass is dissipated.  How much fat will he use up considering the work done only when the weight is lifted up ?  Fat supplies 3.8×107 J of energy per kg which is converted to mechanical energy with a 20% efficiency rate.  Take g = 9.8 ms−2 :

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2.45×10−3 kg

Option 2)

 6.45×10−3 kg

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 9.89×10−3 kg

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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

Option 1)

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

Option 3)

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

Option 4)

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

How many moles of magnesium phosphate, Mg_{3}(PO_{4})_{2} will contain 0.25 mole of oxygen atoms?

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

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Weight fraction of solute

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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

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half that in 8 g He

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558.5 × 6.023 × 1023

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t2) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m2 , the number of rotations made by the pulley before its direction of motion if reversed, is

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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