Chapter 14 Chemical Effects of Electric Current Class 8 Notes

Chemical Effects of Electric Current Class 8 Notes


In the previous year, we read about the Heating Effects of Electric Currents. We also read about the Magnetic Effect of Electric Current.

In this current year, we will read about the Chemical Effects of Electric Current.

Let us look at the best Chemical Effects of Electric Current Class 8 Notes. 

Important topics to be discussed:

  • Electric Current
  • Good Conductors and Poor Conductors
  • Charge carriers- Ions
  • Do Liquids Conduct
  • Chemical Effects of Electric Current
  • Electroplating
  • Applications of Electroplating

Chemical Effects of Electric Current

What are the Chemical Effects of Electric Current

We can see see the Following effects depending on the nature of the solution and electrodes used-

  • metallic deposits on the electrodes
  • change in the color of the solution
  • a release of gas or production of bubbles in the solution

Important Definitions

Electric Current

It is the flow of electric charges through a conductor is electric current or it is the rate of flow of electric charges.

Electric Charges

  • Electrical charges are the sub-atomic particles of an atom. Electrons, protons, and neutrons are sub-atomic particles.
  • The electron carries negative charges, the proton carries positive charges whereas the neutron is neutral i.e., has no charge.
  • Like or the same charges repel each other (positive-positive or negative-negative)
  • Unlike or opposite charges attract each other (positive-negative)

Electric Circuit

a closed loop or path made up of electric components like wire, switch, battery, bulb, etc.


Conductors are the materials that allow electricity to pass through them. Ex- Metals, etc


Materials that do not allow the electric current to pass through them.

Insulators are bad or poor conductors of electricity. Ex- Wood, Plastics, Paper, etc.


The liquids that allow the electric current to pass through it and it itself breaks into ions (charged particles)


are the conductors that allow electricity to pass to non-metals Or poor conductors.


A positively charged electrode is called Anode.


A negatively charged electrode is called a cathode.


these are the charge carriers. When an atom loses or gains electrons, gains a positive or negative charge. Ex – Na+, Cl-, Ca2+ etc


negatively charged ions. Ex- Cl-


positively charged ions. Ex- Na+


It is the process in which a compound breaks into its components by passing an electric current through it.

Applications of Electrolysis

  • Electroplating
  • Purification of metals
  • Extraction of Metals from its ore


It is the process by which a layer of metal is deposited over another metal with the help of an electric current.
Metals that are usually used for electroplating are gold, silver, zinc, etc

Why electroplating is done?

The electroplating is done for the following reasons for electroplating-

  • to protect the parent metal
  • it is cost-efficient
  • It protects the parent metal from corrosion
  • Durability- increases the life span of the metal

Galvanization– When the coating of zinc is done on iron metals to protect them from rusting is called Galvanization.

How Electroplating is done?

The process of electroplating is based on the principle of the chemical effects of electric current.

  • Two electrodes of different metals should be used.
  • The metal on which coating is to be done should be made cathode while the metal to be deposited should be made anode.
  • The electrolyte should be a solution of the metal to be coated.
  • Example- The coating of zinc over a copper plate.

The copper plate is used as a cathode and the zinc plate as an anode, and the zinc sulphate is used as an electrolyte.

How do liquids conduct electricity?

When different substances are mixed in water and electricity is passed through them, it breaks into ions (positive and negative ions) in the water. The more the ion in the liquid, the better the liquid is a conductor.

  • Distilled water is a poor conductor of electricity but salt water is a good conductor of electricity.

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