NCERT Solutions Class 8 Science Chapter 14

NCERT Solutions for Class 8 Science Chapter 14

The study of the world around us is known as science. Scientists gain knowledge about their subjects through observation, description, and experimentation. Science includes a big range of topics and disciplines. For example, some people study space astronomy. Other fields of study include biology, geology, and even matter and energy (physics). The world around us is intriguing, and learning about it can be entertaining and educational.

NCERT Class 8 Science Chapter 14 is Chemical Effects of Electric Current. The first portion of the chapter covers fundamental concepts about electric current and its operation. Students will also learn why handling any electrical item with damp hands is dangerous. The chapter also aims to assist students in comprehending how electricity passes through their bodies and which materials are suitable conductors for electricity to flow freely. Students will also study what constitutes a bad conductor, what could prevent electricity from traveling through these conductors, the operating mechanism, and much more.

Students are generally advised to thoroughly go through the NCERT chapters behind each chapter to cover all essential aspects of the chapter. To put a cherry on the cake, Extramarks presents Class 8 Science Chapter 14 Solution of NCERT. Chemical Effects of Electric Current Class 8 NCERT Solutions are formed to make it straightforward for students to recall all the essential aspects of the chapters.

Extramarks NCERT Solutions provide detailed and authentic answers to all the textbook questions. Through those, the students can understand, remember and retain answers to NCERT questions and thus, perform well in exams.

Not just NCERT Solutions for Class 8 Science Chapter 14, Extramarks is a powerhouse of quality study material. Material such as NCERT books, CBSE revision notes, CBSE sample papers, CBSE previous year question papers, and more can be easily found on the Extramarks website for all classes.

Key Topics Covered in NCERT Solutions For Class 8 Science Chapter 14

Mentioned below are all the key topics that are covered in NCERT Solutions for Class 8 Science Chapter 14- Chemical Effects of Electric Current:

Chemical Effects of Electric Current
Conductors, Insulators and Electric Circuit
Current conducting Liquids
Electrolysis
Electroplating

Let us look at Extramarks’ in-depth information on each subtopic in NCERT Solutions for Class 8 Science Chapter 14- Chemical Effects of Electric Current.

Chemical Effects of Electric Current

According to British scientist William Nicholson, oxygen and hydrogen bubbles occur when the electrodes are submerged in water, and a current is delivered through the water. He observed that hydrogen bubbles developed at the electrode attached to the negative terminal, whereas oxygen bubbles formed at the electrode connected to the positive terminal.

NCERT Solutions for Class 8 Science Chapter 14 explains that Chemical reactions occur when electricity is passed through chemical solutions.

Among those the chemical effects are:

  • Gas bubble creation at electrodes
  • Metal deposition on electrodes
  • Colour changes in the solution

When an electric current is passed across ionic compounds, they dissolve into simpler electrolysis chemicals.

Conductors, Insulators and Electric Circuit

Conductor 

An electrical conductor is described by NCERT Solutions for Class 8 Science Chapter 14 as a substance that allows electricity to flow freely through it. Conductivity is characteristic of conductors that enables them to conduct electricity.

When a charge is applied to such an element, it is dispersed throughout the full surface of the item, causing electrons to flow about within. Charges are transferred to an electrical conductor until the force of repulsion between electrons in locations with surplus electrons is reduced to a minimum. When such an item comes into touch with another conductor, the charge is transferred from the first conductor to the second, reducing total charge repulsion.

All metals, people, as well as the earth are good conductors of electricity. This is why we get electric shocks! Some examples of common conductors are metals such as:

  • Iron
  • Copper
  • Gold

Insulators

NCERT Solutions for Class 8 Science Chapter 14 describes Insulators as materials that prevent electrons from freely flowing from one element particle to another. If we apply a charge to such an element at any point on the surface, the charge remains in the same place and does not spread throughout the surface. Charging by rubbing is the most prevalent method of charging such components (for some elements, with the help of suitable materials). Some quickly found Insulators are:

  • Glass
  • Wood
  • Plastic

Electric Circuit

Electric circuits are closed-loop or route systems that consist of a network of electrical components through which electrons can travel. This route is made up of electrical cables powered through a battery. The source is the point where electrons begin to flow, and the return is the point where electrons depart from the electrical circuit.

Only one closed loop from the positive to the negative end completes an electrical circuit. This is the most basic type of an electric circuit; the circuit inside a television is more sophisticated and contains more components.

NCERT Solutions for Class 8 Science Chapter 14 highlights that faulty electrical circuits produce fires; water should not be used to extinguish flames caused by electrical failure; special extinguishers are available for this purpose.

For electric current to flow, a continuous connection from a battery to various components and back to the battery is a must; any disruption to this connection will cause the current to discontinue flowing.

Tester

An electric component known as a tester is used to verify the presence of electric current in a circuit. It has an LED lamp that helps indicate whether there is an electric current present.

Extramarks NCERT Solutions for Class 8 Science Chapter 14 explains the concepts of Conductors, Insulator and Electric Circuit in the above section. For any more information on this or other topics, please refer to the Extramarks website.

Current conducting Liquids

Conducting Liquid:

  • When salts are dissolved in the liquid, it works as electricity.
  • Most fluids that conduct electricity are acids, bases, or salt solutions.

Acids, Bases and Salts

  • Acids, as well as bases, are chemical compounds that dissociate to generate ions when dissolved in a solution because the ions are an excellent conductor of electricity.
  • Salts conduct when dissolved in water because they produce positive and negative ions.

Conduction of Electricity in Water:

  • As distilled water lacks dissolved salts and minerals, distilled water is a poor conductor of electricity.
  • When acids, bases, or salts are dissolved in water, ions are released, which conduct when a potential difference is applied.

Electrodes and Electrolyte:

  • An electrode is a conductor submerged in a solution and has one end linked to the terminals of a battery, completing a circuit. The cathode (ve) and anode (+ve) electrodes are typically used.
  • A fluid in which the electrodes are immersed is called an electrolyte. They separate when an electric current passes through them.
  • The electrochemical/electrolytic cell comprises electrodes, electrolytes, and a battery.

In the above section, Extramarks NCERT Solutions for Class 8 Science Chapter 14 briefly describes the current conducting in liquids. Extramarks is your one-stop solution for quality study material in abundance. Refer to the website today.

Electrolysis

Another important concept that NCERT Solutions for Class 8 Science Chapter 14 discusses is Electrolysis. A chemical change occurs when current is carried through an electrolytic solution, dissociating electrolytes into their constituent ions. This is referred to as Electrolysis.

An electrolytic cell is necessary for Electrolysis to take place. The electrodes in this cell are commonly metal rods dipped in an acidic, basic, or salt solution to complete a circuit with liquid conductors. These electrodes are linked to batteries by a switch. The terminals of a battery are positively and negatively charged. An electrode is characterized as a cathode (when coupled to the negative terminal) or anode (when attached to the positive terminal) depending on which terminal it is connected to (when connected to the positive terminal)

Electrolysis is used in:

  • Some metals are extracted and purified using this method. The method is known as electrorefining.
  • It’s used in the electroplating process.

Electroplating

Electroplating is the technique of putting over a coating of chosen metal on another material using electricity and using Copper Sulphate solution as an electrolyte and copper electrodes as an example. On the negative electrode, copper is electroplated. The addition of copper ions from the positive electrode replenishes the Cu in the solution.

Some applications of Electroplating are

  • Zinc coating on iron to prevent rust and corrosion.
  • Silver and gold plating for jewelry.
  • Because tin is less reactive than iron, it is used to coat cans.
  • Due to its lustrous look, chromium plating is used for vehicle parts and bath fittings.

Extramarks NCERT Solutions for Class 8 Science Chapter 14 explains the significant concept of Electroplating in the above section. In addition, Extramarks is a house to various other study materials for all classes.

NCERT Solutions For Class 8 Science Chapter 14 Exercise and Solutions

Extramarks NCERT solutions provide detailed and authentic answers to all the textbook questions. Through those, the students can understand, remember and retain answers to NCERT questions and thus, perform well in exams.

The main focus of Extramarks is to present students with good quality study material. Team Extramarks has taken a step towards it by producing NCERT Solutions for each chapter. These solutions are designed for each chapter and can be found on the Extramarks website. Click on the below links to view NCERT Solutions for Class 8 Science Chapter 14:

Class 8 Science Chapter 14: Very Short Answer Type Questions

Class 8 Science Chapter14: Short Answer Type Questions

Class 8 Science Chapter14: Long Answer Type Questions

Students may access NCERT Solutions for Class 8 Science Chapter 14 and other chapters by clicking here. In addition, students can also explore NCERT Solutions for other classes below.

By accessing NCERT Solutions for Class 8 Science Chapter 14, students can easily understand all the Chemical Effects of Electric Current concepts.

NCERT Solutions Class 8 Science Chapter-wise List

Chapter 1 – Crop Production and Management
Chapter 2 – Microorganisms : Friend and Foe
Chapter 3 – Synthetic Fibres and Plastics
Chapter 4 – Materials : Metals and Non-Metals
Chapter 5 – Coal and Petroleum
Chapter 6 – Combustion and Flame
Chapter 7 – Conservation of Plants and Animals
Chapter 8 – Cell – Structure and Functions
Chapter 9 – Reproduction in Animals
Chapter 10 – Reaching The Age of Adolescence
Chapter 11 – Force and Pressure
Chapter 12 – Friction
Chapter 13 – Sound
Chapter 14 – Chemical Effects of Electric Current
Chapter 15 – Some Natural Phenomena
Chapter 16 – Light
Chapter 17 – Stars and The Solar System
Chapter 18 – Pollution of Air and Water

Key Features of NCERT Solutions For Class 8 Science Chapter 14

To do well in their upcoming examination, students must go over the fundamentals completely. Extramarks’ NCERT Solutions make it simpler for students to prepare well. In addition, NCERT Solutions for Class 8 Science Chapter 14 gives comprehensive information about the chapter, assisting students in their preparation. Some of the reasons why you should be choosing Extramarks are as follows:

  • The solutions are formed so that they tend to solve almost all the doubts of the students.
  • These solutions have proven to be time-saving for students.
  • After learning from these solutions, students are filled with confidence.

Q.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 ______________.

Ans-

(a) Most liquids that conduct electricity are solutions of acid, bases and salts.
Explanation: The solutions of acids, bases or salts can conduct electricity.

(b) The passage of an electric current through a solution causes chemical effects.
Explanation: The solution decomposes into positive and negative ions when electric current passes through it.

(c) If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the negative terminal of the battery.
Explanation: On passing an electric current through a copper sulphate solution, the solution decomposes into positively charged copper ions and negatively charged sulphate ions. The positively charged copper ions get attracted towards the plate which is 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.

Q.2 When the free ends of a tester are dipped into a solution, the magnetic needle shows deflection. Can you explain the reason?

Ans-

The deflection in the compass needle proves that current is flowing through the circuit. It shows that the solution is a conducting solution.

Q.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 such as lemon juice, salt water and vegetable oil allow electricity to pass through them. Therefore, these liquids can be used in the beaker shown here.

Q.4 The bulb does not glow in the setup shown in Fig.14.10. List the possible reasons. Explain your answer.

Ans-

There may be two reasons for this.

(i) The battery connected in the circuit has insufficient energy to generate electricity.
(ii) Liquid kept in the beaker is non-conducting. In this case, current would not be able to pass through the liquid.

Q.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-

The correct option is (i).

Explanation: The magnitude of current flowing through a conducting solution depends on the conductivity of the solution. The solution having more conductivity will allow more current to pass through it.

Q.6 Does pure water conduct electricity? If not, what can we do to make it conducting?

Ans-

No,Pure water does not conduct electricity because it does not contain salt. When some common salt is added to the pure water, it can conduct electricity.

Q.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-

Water can act as a conductor of electricity. In case of a fire, if the electrical supply for the area is not shut off and water is poured over electrical appliances, then the fireman can get electric shocks.

Q.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-

Sea water is more salty than the drinking water. Therefore, it is more conducting than the drinking water. Due to this, the compass needle deflects more in the case of seawater than in the drinking water.

Q.9 Is it safe for the electrician to carry out electrical repairs outdoors during heavy downpour? Explain.

Ans-

No, During heavy downpour, it is not safe to repair electrical appliances outdoors. Rain water can conduct electricity as it contains dissolved salts. Hence, the electrician may get electrical shocks while working outdoors during rain.

Q.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-

Rain water acts as conducting solution as it contains dissolved salts. On the other hand, there are no dissolved salts present in the distilled water. Therefore, rain water can allow electricity to pass through it.

Q.11 Prepare a list of objects around you that are electroplated.

Ans-

  1. In gold-plated ornaments, a fine layer of gold is deposited on the silver ornaments.
  2. Chromium plating is done on different parts of vehicles to make them shiny.
  3. To protect iron from corrosion, iron is coated with zinc layer.

Q.12 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 transfered to the thin copper plate. Which electrode should be attached to the positive terminal of the battery and why?

Ans-

Copper ions have positive charges. Hence, they are attracted towards the plate which is connected to the negative terminal of the battery. As copper ions are transferred to the thin copper plate, this thin pure copper plate should be connected to the negative terminal of the battery. As a result, impure copper rod should be connected to the positive terminal of the battery.

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FAQs (Frequently Asked Questions)

1. What is the focus of the 14th chapter of Class 8 Science for students?

Students will discover in this chapter that certain liquids are great conductors of electricity while others are not. Furthermore, most electrically conducting liquids are combinations of acids, bases, and salts. They will also learn that the passage of an electric current through a conducting liquid causes chemical reactions. Finally, students will learn about Electroplating, which is applying a coating of any metal to another item using electricity.

2. Why is zinc applied to iron?

Galvanization is the process of covering iron with a layer of zinc. Because iron is a highly durable and robust metal, it is employed in the building. However, due to the development of hydrated ferric oxide, iron corrodes and rusts when exposed to air and moisture. Therefore a zinc coating is applied to iron to prevent corrosion and prevent rust development.