WorksheetsScience Quiz on Chemical Reactions Monika Mehta
Total questions: 8
Worksheet time: 9mins
Narinder Singh is performing an experiment to study the electrolysis of water. After a few minutes, he observes gas bubbles Oxygen forming at both electrodes, but he notices that twice the volume of gas is collected at one electrode compared to the other. Why is the volume of gas collected at the cathode twice that at the anode?
Hydrogen is denser than oxygen.
Electrodes have different sizes
For every water molecule, 2 hydrogen atoms and 1 oxygen atom is released.
Oxygen dissolves in water easily
Arshdeep takes a clean iron nail and dips it into a solution of CuSO4. After leaving it for a while, he observes that the blue colour of the solution fades and a reddish-brown layer forms on the iron nail. What kind of reaction has taken place between iron and copper sulphate?
Iron is dissolving in water.
Rusting is occurring due to reaction with air and moisture.
A physical change has occurred
Rainwater deposits mud which appears red in colour.
Solution A, B, C and D have pH 1.5, 4, 6.5 and 10. The solution with highest basic gradually turned gray. What is the most likely cause of the color change observed in silver chloride?
Silver chloride reacts with oxygen in the air to form silver oxide.
Silver chloride decomposes in sunlight to form silver metal and chlorine gas.
Silver chloride melts in sunlight, causing a colour change.
Silver chloride reacts with moisture to form hydrochloric acid.
What happens when iron reacts with copper sulphate solution to form iron sulphate and copper?
Iron is reduced, copper is oxidized
Combination reaction
Double displacement reaction
Decomposition reaction
Displacement reaction
Which one of the following is not a chemical change?
Photosynthesis
Digestion of food
Evaporation of water
Respiration
Aman left his iron bicycle out in the rain. After a week, he noticed reddish-brown flakes on the surface of the metal. He wiped them off, but they kept coming back after each rain. What does this situation indicate?
Rajwinder was doing a science project on soil quality. She tested the pH of the soil in her garden and found it to be around 5.5. She noticed that some plants were not growing well. Her teacher suggested adding a substance to improve the soil condition for better plant growth. Which substance should Rajwinder add to the soil and why?
Dilute hydrochloric acid, to increase acidity.
Lime (calcium oxide), to reduce acidity.
Common salt, to provide essential minerals.
Baking soda, to make the soil alkaline.
During a science activity, Sukhjit took a small amount of silver chloride (AgCl) in a china dish and placed it under sunlight. After some time, he noticed that the white mixture
