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. Which of the following is a chemical effect of electric current? Deposition of metals on the electrodes Formation of gas bubbles on the electrodes All of the above Change of color of solution None 2. Chemical effect of electric current may cause : formation of gas bubbles at the electrodes all of above deposit of metal on the electrodes change in colour of the solution None 3. Which of the following gas is formed at the electrode connected to the negative terminal of the battery? Nitrogen gas Carbon dioxide gas Oxygen gas Hydrogen gas None 4. 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 5. 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 A is a better conductor than liquid B both liquids are equally conducting liquid B is a better conductor than liquid A conducting properties of liquid cannot be compared in this manner None 6. Which of the following is an example of electroplating? All of the above Coating of chromium on many objects such as bath taps, car parts, etc. Coating of gold or silver on less expensive metals Coating of zinc on tin to make cans None 7. 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? Greenish blue spot on potato around both wires Greenish blue spot on potato around one wire. Blue color spot on potato around both wires. Blue color spot on potato around one wire None 8. Which of the following statement is correct while testing for conduction of electricity in lemon juice using an LED tester? The current flows in the circuit of the 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. None 9. When electric current is passed through water, dissociation is indicated __________ none of above both a and b in the form of bubbles by color change None 10. If electrodes are immersed in water and a current was passed, bubbles of ___________ and __________ are produced. oxygen and hydrogen hydrogen and carbon dioxide nitrogen and carbon dioxide oxygen and carbon dioxide None 11. When electric current is passed through water, hydrogen is deposited over : no dissociation negative pole both the poles positive pole None 12. Which of the following gas is formed at the electrode, connected to the positive terminal of the battery? Carbon dioxide gas Oxygen gas Hydrogen gas Nitrogen gas None 13. Which of the following is added to make the copper sulphate solution more conducting? Carbonic acid Sulphuric acid Nitric acid Hydrochloric acid None 14. 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 15. What will happen, When an electric current is passed through a conducting solution? heating of solution increase in resistance cooling of solution chemical reactions within the solution None 16. 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. Both Assertion and Reason is correct and Reason is the correct explanation of Assertion Assertion is incorrect and Reason is correct Assertion is correct and Reason is incorrect Both Assertion and Reason is correct but Reason is not the correct explanation of Assertion None 17. In the experiment to test for conduction of electricity through a potato, the greenish blue color spot on the potato is useful in identifying : neither A nor B both A and B the positive terminal the negative terminal None 18. Why do jewellery makers electroplate gold or silver on metals? To prevent spoilage of jewellery. To make it shine. To reduce cost. To protect it from corrosion. None 19. The chemical effect produced by an electric current depends on: the nature of electrode the tester the conducting solution none of the above None 20. 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 lighter than Iron Tin is less reactive than Iron Tin is more reactive than Iron Tin is cheaper than Iron 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.
