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myCBSEguide, , Class 10 - Science, Term 1 - Chemical Reactions and Equations - 03, 1. In the electrolysis of water, at which electrodes are hydrogen and oxygen collected?, a. graphite rods, metal rods, b. cathode, anode, c. anode, cathode, d. graphite rods, non-metal rods, 2. Which one of the following will be required to identify the gas evolved when diluted HCl reacts with, zinc metal?, a. Red litmus solution, b. Blue litmus solution, c. A burning splinter, d. Lime water, 3. The taste and smell of food changes when kept for a long time in open. It is called, a. Rancidity, b. Corrosion, c. Oxidation, d. Reduction, 4. Silver articles on exposure become black. It is an example of, a. Oxidation reaction, b. Corrosion, c. Reduction reaction, d. Redox reaction, 5. Chemically rust is:, a. Metal oxide, b. Ferric oxide, c. Ferrous oxide, d. Hydrated ferric oxide, To practice more questions & prepare well for exams, download myCBSEguide App. It provides, complete study material for CBSE, NCERT, JEE (main), NEET-UG and NDA exams., 6. Evaporation of water is an example of, a. Combination reaction, b. Oxidation reaction, c. Chemical change, d. Physical change, 7. Which of the following gases can be used for storage of fresh sample of an oil for a long time?, a. Carbon dioxide or helium, b. Nitrogen or oxygen, c. Carbon dioxide or oxygen, d. Helium or nitrogen, 8. The odour of SO2 gas is, a. Odourless, b. Pungent, c. Sweet smelling, , Copyright © myCBSEguide.com. Mass distribution in any mode is strictly prohibited., , 1/5
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myCBSEguide, d. Foul smelling, 9. Which of the statements about the reaction below are incorrect?, 2PbO(s) + C(s) → 2Pb(s)+CO2(g), a. Lead is getting reduced., b. Carbon dioxide is getting oxidised., c. Carbon is getting oxidized., d. Lead oxide is getting reduced., a. (c) and (d), b. (a) and (c), c. (a) and (b), d. (a), (b) and (c), 10. What happens when copper metal is added to the silver nitrate solution?, a. Cu will be reduced whereas silver will be oxidesed, b. None of these, c. Cu(NO3)2 will be formed, d. Copper can’t displace silver from its solution, 11. A student added zinc granules to copper sulphate solution taken in a test tube. Out of the following, the, correct observation (s) made by the student will be, A. Zinc granules have no regular shape., B. Zinc granules have silvery grey colour., C. The colour of zinc granules changed to brownish-black., a. C only, b. A, B and C, c. B only, d. A only, For question numbers 12-15, two statements are given- one labeled Assertion (A) and the other labeled, Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given, below:, a., b., c., d., , Both A and R are true and R is the correct explanation of A., Both A and R are true but R is not the correct explanation of A., A is true but R is false., A is false but R is true., , To practice more questions & prepare well for exams, download myCBSEguide App. It provides complete study, material for CBSE, NCERT, JEE (main), NEET-UG and NDA exams., 12. Assertion: Pungent smelling gas is produced when sulphur burns in air., Reason: Sulphur trioxide is formed on reaction of sulphur with oxygen., 13. Assertion: White silver chloride turns grey in sunlight., Reason: Decomposition of silver chloride in the presence of sunlight takes place to form silver metal and, chlorine gas., 14. Assertion: Photosynthesis is considered as an endothermic reaction., Reason: Energy gets released in the process of photosynthesis., 15. Assertion: Brown fumes are produced when lead nitrate is heated., Reason: Nitrogen dioxide gas is produced as a byproduct due to the decomposition of lead nitrate., , Copyright © myCBSEguide.com. Mass distribution in any mode is strictly prohibited., , 2/5
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myCBSEguide, Answer questions 16-20 based on the following case study:, Read the passage given below and answer the following questions:, In a redox reaction, both oxidation, as well as reduction, takes place together, oxidation involves loss of, electrons while reduction involves the gain of electrons. The redox- reaction may involve a combination of, atoms and molecules, displacement of metals, or non-metals., Example: CuSO4 + Zn, ZnSO4 + Cu, displacement of Cu metal from its compound., 16. In the above equation, which of the following gets reduced?, a. CuSO4, b. Zn, c. ZnSO4, d. None of these, 17. The oxidising agent generally:, a. loses the electrons, b. gains the electron, c. is in a gaseous state, d. both b and c, 18. Identify the oxidising agent and reducing agent in the above reaction, a. Copper, Zinc, b. Zinc, Copper, c. Zinc, Zinc, d. Copper, Copper, 19. Identify the type of reaction., a. Double displacement reaction, b. Displacement reaction, c. Substitution reaction, d. Addition reaction, 20. Based on the electrolysis of different solutions in water comment whose electrolysis will be the fastest, , a., b., c., d., , lemon water, baking soda, salt, vinegar, , Copyright © myCBSEguide.com. Mass distribution in any mode is strictly prohibited., , 3/5
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myCBSEguide, Term 1 - Chemical Reactions and Equations - 03, Class 10 - Science, Solution, 1. (b) cathode, anode, Explanation: According to electrolysis reaction, H + ions pick up electrons from the cathode and get, reduced to H2 gas, while oxide ions lose their electrons at the anode and get oxidized to oxygen gas., , 2. (c) A burning splinter, Explanation: Zinc is a reactive metal which on reaction with HCl produces hydrogen gas, which burns, with a pop sound., Zn + 2HCl, ZnCl2 + H2 ↑, 3. (a) Rancidity, Explanation: Rancidity is defined as chemical decomposition of oils and fats which in other words is, spoiling food materials that is difficult for consumption. It is used to denote unpleasant odours and, flavours in foods resulting from deterioration in the fat or oil portion of food., 4. (b) Corrosion, Explanation: Silver is known to be resistant to corrosion, as it does not oxidize easily. When silver is, exposed to air, a layer of silver sulfide is formed on the surface., 2Ag(s) + H2S(g), Ag2S(s) + H2(g), 5. (d) Hydrated ferric oxide, Explanation: Rust is an iron oxide, a usually red oxide formed by the redox reaction of iron and, oxygen in the presence of water or air moisture. Chemically, rust is a hydrated ferric oxide (Fe2O3., H2O)., To practice more questions & prepare well for exams, download myCBSEguide App. It provides, complete study material for CBSE, NCERT, JEE (main), NEET-UG and NDA exams., 6. (d) Physical change, Explanation: Evaporation is a physical change because when water evaporates no new substances are, being made or nothing is being taken away from it, so, in that case, it is still water. It is reversible. It is, not permanent., 7. (d) Helium or nitrogen, Explanation: Oxygen cannot be used as it is an oxidizing agent. Helium can be used as it is an inert, Copyright © myCBSEguide.com. Mass distribution in any mode is strictly prohibited., , 4/5
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myCBSEguide, gas. Nitrogen is less reactive and it is cheaper than Helium. In most cases nitrogen is used in packet to, prevent rancidity., 8. (b) Pungent, Explanation: Sulfur dioxide is the chemical compound with the formula SO2. It is a toxic gas with a, pungent, irritating smell. It is released naturally by volcanic activity and is produced as a by-product of, the burning of fossil fuels contaminated with sulfur compounds., 9. (c) (a) and (b), Explanation: Here, lead oxide loses oxygen and hence reduced. Carbon gains oxygen and hence, oxidized. And not lead is getting reduced. Carbon dioxide is not getting oxidized., 10. (c) Cu(NO3)2 will be formed, Explanation: When copper metal is added to the silver nitrate solution then Cu(NO3)2 will be formed., , 16., , This is displacement as well as a redox reaction., (b) A, B and C, Explanation: Zn granules are silvery grey of variable sizes and displace Cu from its compound to turn, brownish in colour., (c) Assertion is CORRECT but, reason is INCORRECT., Explanation: Assertion is CORRECT but, reason is INCORRECT., (a) Both assertion and reason are CORRECT and reason is the CORRECT explanation of the assertion., Explanation: Both assertion and reason are CORRECT and reason is the CORRECT explanation of the, assertion., To practice more questions & prepare well for exams, download myCBSEguide App. It provides, complete study material for CBSE, NCERT, JEE (main), NEET-UG and NDA exams., (b) Both assertion and reason are CORRECT but, reason is NOT THE CORRECT explanation of the, assertion., Explanation: Both assertion and reason are CORRECT but, reason is NOT THE CORRECT explanation of, the assertion., (a) Both assertion and reason are CORRECT and reason is the CORRECT explanation of the assertion., Explanation: Both assertion and reason are CORRECT and reason is the CORRECT explanation of the, assertion., (a) CuSO4, , 17., 18., 19., 20., , (b) gains the electron, (a) Copper, Zinc, (b) Displacement reaction, (a) lemon water, , 11., , 12., 13., , 14., , 15., , Copyright © myCBSEguide.com. Mass distribution in any mode is strictly prohibited., , 5/5
