Ncert – class 8- science – Chapter 11: Chemical Effects of Electric Current 1 Welcome to your Ncert - class 8- science - Chapter 11: Chemical Effects of Electric Current 1 1. What will happen, When an electric current is passed through a conducting solution? chemical reactions within the solution increase in resistance heating of solution cooling of solution None 2. The chemical effect produced by an electric current depends on: the tester the conducting solution none of the above the nature of electrode None 3. LED is better than bulb to use in a tester as : it is cheaper. all of the above it emits more light. it glows even when weak current passes through it. None 4. A tester is used to check the conduction of electricity through two liquids, labeled 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: liquid B is a better conductor than liquid A conducting properties of liquid cannot be compared in this manner liquid A is a better conductor than liquid B both liquids are equally conducting None 5. Which of the following gas is formed at the electrode connected to the negative terminal of the battery? Oxygen gas Nitrogen gas Hydrogen gas Carbon dioxide gas None 6. Which of the following is true during electroplating? The metal gets transferred from one electrode to another All of the above The metal gets deposited from positive terminal of a battery to negative terminal of the battery. Some amount of metal gets dissolved in the solution of the electrolyte. None 7. Which of the following gas is formed at the electrode, connected to the positive terminal of the battery? Oxygen gas Nitrogen gas Carbon dioxide gas Hydrogen gas None 8. Tin cans are the tin electroplated on iron. These Tin cans are used to preserve food items. Why not iron cans used without Tin coating? Tin is less reactive than Iron Tin is cheaper than Iron Tin is more reactive than Iron Tin is lighter than Iron None 9. Chemical effect of electric current may cause : change in colour of the solution all of above deposit of metal on the electrodes formation of gas bubbles at the electrodes None 10. In the experiment to test for conduction of electricity through potato, which of the following observations indicate that a potato is a conductor of electricity? Blue color spot on potato around one wire Blue color spot on potato around both wires. Greenish blue spot on potato around both wires Greenish blue spot on potato around one wire. None 11. Which of the following is added to make the copper sulphate solution more conducting? Nitric acid Carbonic acid Sulphuric acid Hydrochloric acid None 12. In the experiment to test for conduction of electricity through a potato, the greenish blue color spot on the potato is useful in identifying : both A and B the negative terminal the positive terminal neither A nor B None 13. Which of the following is a chemical effect of electric current? Deposition of metals on the electrodes Change of color of solution All of the above Formation of gas bubbles on the electrodes None 14. When electric current is passed through water, hydrogen is deposited over : positive pole no dissociation negative pole both the poles None 15. If electrodes are immersed in water and a current was passed, bubbles of ___________ and __________ are produced. nitrogen and carbon dioxide hydrogen and carbon dioxide oxygen and hydrogen oxygen and carbon dioxide None 16. Which of the following is an example of electroplating? Coating of chromium on many objects such as bath taps, car parts, etc. Coating of zinc on tin to make cans All of the above Coating of gold or silver on less expensive metals None 17. When electric current is passed through water, dissociation is indicated __________ none of above in the form of bubbles by color change both a and b None 18. Assertion:Chromium plating is done on many objects like car parts, wheel rims and bath taps.Reason:The chromed layer can be decorative, provide corrosion resistance, ease cleaning procedures, or increase surface hardness. Assertion is incorrect and Reason is correct Both Assertion and Reason is correct but Reason is not the correct explanation of Assertion Both Assertion and Reason is correct and Reason is the correct explanation of Assertion Assertion is correct and Reason is incorrect None 19. Why do jewellery makers electroplate gold or silver on metals? To make it shine. To reduce cost. To prevent spoilage of jewellery. To protect it from corrosion. None 20. Which of the following statement is correct while testing for conduction of electricity in lemon juice using an LED tester? All of the above The liquid (lemon juice) allows the electric current to pass through. Hence, the circuit of tester is complete. The bulb glows which indicates lemon juice is a good conductor of electricity. The current flows in the circuit of the tester. None Time's up Please Share This Share this content Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Leave a Reply Cancel replyCommentEnter your name or username to commentEnter your email address to commentEnter your website URL (optional) Save my name, email, and website in this browser for the next time I comment.
