CBSE – 8th Standard Science

CBSE - 8th Standard Science

Question Bank – Chapter 14 – Chemical Effects of Electric Current




Q1. What is chemical effect of electricity?

Ans. The passage of an electric current through a conducting liquid causes chemical reactions.  The resulting effects are called chemical effects of currents.


Q 2. What makes a liquid conductor of current?

Ans. Most liquids are solutions of acids, bases and salts; it makes them a conductor of electricity.


Q3. What happens when electric current is passed with the help of a battery through the copper sulphate solution?

Ans. When electric current is passed through the copper sulphate solution, copper sulphate dissociates into copper and sulphate. The free copper gets drawn to the electrode connected to the negative terminal of the battery and gets deposited on it.


Q 4. Why canes of iron are electroplated with tin?

Ans. Tin is less reactive than iron. Thus, food does not come into contact with iron and is protected from getting spoilt.


Q 5. What is electroplating?

Ans. The process of depositing a layer of any desired metal on another material by means of electricity is called electroplating.


Q 6. What are the common applications of chemical effects of electric current?

Ans. Electroplating is one of the most common applications of chemical effects of electric current.


Q 7. What are some of the uses of chromium plating?

Ans. Chromium plating is done on many objects such as car parts, bath taps, kitchen gas burners, bicycle handlebars, wheel rims and many others.


Q 8. Does pure water conduct electricity? If not, what can we do to make it?

Ans. Pure water is not a good conductor of electricity, if some salt is added; it will be a good conductor.


Q 9. What is the main advantage of chromium plating?

Ans. The main advantage of chromium plating is chromium has a shiny appearance. It does not corrode. It resists scratches.


Q 10. How iron is protected from rusting?

Ans. Iron tends to corrode and rust. So, a coating of zinc is deposited on iron to protect it from corrosion and formation of rust.


Try these:

  • 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.
  • 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?
  • Is it safe for the electrician to carry out electrical repairs outdoors during heavy downpour? Explain.
  • Describe the specific features of an LED?
  • Chrome plating is very popular in the industry. What are its pros and cons?
  • Why is it dangerous to handle electrical appliances with wet hands or while standing on a wet floor ?