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DELHI PUBLIC SCHOOL R. N. EXTENSION, PRE-BOARD-I EXAMINATION (2021-22), SCIENCE (086), CLASS-X (SET-B), Shawy..., hanya, Name: .., Section:, Date: ..../0 (21, No. of sides printed: 13, Roll No.:, No. of Questions:60, Time: 1.5-hour, Maximum Marks: 40, General Instructions:, 1. The Question Paper contains three sections., 2. Section A has 24 questions. Attempt any 20 questions., 3. Section B has 24 questions. Attempt any 20 questions., 4. Section C has 12 questions. Attempt any 10 questions., 5. All questions carry equal marks., 6. There is no negative marking., SECTION A, Section -A consists of 24 questions. Attempt any 20 questions from this section., The first attempted 20 questions would be evaluated, Q.1. When the gases sulphur dioxide and hydrogen sulphide mix in the presence of water, the following, reaction takes places:, SO 2++2 H.S-2 H2O + 3S, Here, hydrogen sulphide is acting as:, A. an oxidizing agent, B. a reducing agent, C. a dehydrating agent, D. a catalyst, Q. 2. Which of the following are correctly matched?, 1., Plants and animals, pH range is 7.0 to 7.8, 2., Rain water, pH is 7.6, Tooth decay, pH less than 5.5, A. 1 and 2, B, 2 and 3, L. 1 and 3, D. 1,2 and 3, Page 1 of 13, Scanned by TapScanner, 3.

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Q.3. What happens when dilute hydrochloric acid is added to iron fillings?, X. Hydrogen gas and iron chloride are produced., B. Chlorine gas and iron hydroxide are produced., C. No reaction takes place., D. Iron salt and water are produced., Q.4. Calcium oxide reacts vigorously with water., Beaker, Water, Calcium oxide, Identify the incorrect statements., 1. It is an endothermic reaction., 2. Slaked lime is produced., 3. Quick lime is produced., 4. It is an exothermic reaction., 5. It is a combination reaction., A. 1 and 2, B. 3 and 4, C. 1 and 3, D. 2, 4 and 5, Q.5. A metal carbonate reacts with a solution X which forms a salt, water, and a gas Y. What are X and Y?, A. X: hydrochloric acid; Y: hydrogen, B. X: sodium hydroxide; Y: hydrogen, e. X: hydrochloric acid; Y: carbon dioxide, D. X: sodium hydroxide; Y: carbon dioxide, Q.6. Generally, metals react with acids to give salt and hydrogen gas. Which of the following acids does, not give hydrogen gas on reacting with metals (except Mn and Mg)?, A. H2SO4, В. НС!, J.HNO3, D. All of these, Q.7. A student adds lead and silver to two different test tubes containing an equal amount of copper, sulphate solution. The student observes that the color of the solution in the test tube with lead changes., What explains the change in the colour of the solution?, K. A displacement reaction takes place as lead replaces copper from the solution., B. A combination reaction takes place as lead combines with sulphate in the solution., C. A decomposition reaction takes place as copper dissociates from sulphate in the solution., D. A double displacement reaction takes place as copper dissociates from sulphate and lead, combines with sulphate in the solution., Page 2 of 13, Scanned by TapScanner

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Q.8. Carefully study the diagram of the human respiratory system. Select the option which gives correct, identification and main function, B., D., Pharynx, common, passage for food and conducts air into of gases, air, Bronchus,, Alveoli, exchange Diaphragm, allow the, lungs to expand and, lungs, contract, Epiglottis, allow air, to pass into larynx, Alveoli,, exchange of, Bronchus,, conducts air into, Diaphragm, allow the, lungs to expand and, gases, lungs, contract, Diaphragm, allow the, lungs to expand and, C., Trachea, wind, pipe, Larynx, voice box, Bronchioles,, exchange of, gases, contract, Diaphragm, allow the, exchange of gases lungs to expand and, Bronchioles,, Trachea, wind, pipe, D., Larynx, voice box, contract, Q.9. Observe the diagram of the human digestive system, Match the labeling referred in column I and correlate with the function in column II, Column I, Column II, i. Emulsification of fats, ii. Reabsorption, R., R., iii Partial digestion, iv Secretion of saliva, A. P-i, Q-ii, R-iii, S-iv, B. P-iv, Q-iii, R-i, S-ii, C. P-iii, Q-iv, R-ii, S-i, D. P-ii, Q-iii, R-i, S-iv, Page 3 of 13, Scanned by TapScanner, 380, A.

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Q.10. An experimental arrangement of formation of gas is shown in the figure: Which gas is present in tube, A?, A. Oxygen, B. Hydrogen, C. Helium, D. Nitrogen, 10, Water, Graphite, rod, Rubber, stopper, Anode, Cathode, 6 V, Battery, Switch, Q.11 When pH strip is dipped in each bottle, the colour shown by bottle A and B will be respectively:, A. orange, blue, B. blue, orange, C. green, blue., D. blue, green, Oxalic, Sodiun, carbonate, solution, acid, (A), (B), Q.12 Four student- 'A', 'B', C' and D measured pH value of water, lemon juice and sodium bicarbonate, solution. The student who has expressed correct pH values in decreasing order., A. Water > lemon juice > Sodium bicarbonate, B. Lemon juice > Water > Sodium bicarbonate solution, C. Sodium bicarbonate solution, D. Water > Sodium bicarbonate solution > lemon juice, solution, > water > lemon juice, Q. 13. Breathing is a process that, (i) Provides O2 to the body., (ii) breaks down food to release energy., (iii) helps the body to get rid of CO2, (iv) produces water in the cells., Which of the following gives the correct combination of functions of breathing?, A. (i) and (ii), B. (ii) and (iii), e. (i) and (iii), D. (ii) and (iv), Q.14 A ray of light that strikes a plane mirror PQ at an angle of incidence of 30o, is reflected from the, plane mirror and then strikes a second plane mirror QR placed at right angles to the first mirror. The angle, of reflection at the second mirror is:, А. 30°, В. 45°, С. 60°, D. 90°, Page 4 of 13, Scanned by TapScanner

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Q.15 Identify the concentrating segment in the given diagram of nephron, A. X, Renal Artery, B. Y, Renal Vein, C. A, Collecting Duct, D. B, Renal Tubule, Q.16 Stomata open during the daytime because the guard cells, A. photosynthesize and produce osmotically active sugars, B. are thin walled, C. are bean shaped, D. to avoid loss of water, Q.17 The figure given below shows the various parts of human heart with labels 1 to 9.Identify the correct, sequence of blood circulation through various parts, 1 & 3: Right & Left Atrium, 2 & 4: Right & Left Ventricle, 5 & 9: Pulmonary Artery & Pulmonary Vein, 6: Aorta, 5R, 7& 8: Superior & Inferior Vena Cava, A. 1-2-3-4 56→7→8 & 9, B. 1-2-7-5-9-6-3→4 & 8, C. 1-2-5-9→3-4-6→7 & 8, D. 1-2-7 9 8-3→4 5 & 6, Q. 18. A light ray enters from medium A to medium B as shown in below Figure. Therefractive index of, medium B relative to A will be, K. greater than unity, B. less than unity, C. equal to unity, D. zero, Medium B, Medium A, Page 5 of 13, Scanned by TapScanner