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CSSC- TIRUVALLUR CLUSTER, Pre Board Examination- 2021(Term-1), CLASS- X, SCIENCE- (086), Time Allowed : 90 Mins, , 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.), 1. A teacher performed an experiment to explain the characteristics of chemical reaction to her students., She took a metal P, cleaned its surface and burned it by holding it with a pair of tongs using a burner as, shown in the figure:, , A white dazzling flame was observed and a powder Q was obtained in the watch glass. Identify P and Q, and select the row containing the correct observations:, P, , Q, , Colour of Q, , (a), , Mn, , MnO2, , White, , (b), , Mg, , MgO, , White, , (c), , Mg, , MgCO3, , Green, , (d), , Ag, , Ag2O, , Grey, , 2. Match the chemical substances given in column I with their appropriate use/ application given in column, II:, Column I, , Column II, , (I) Baking Soda, , (A) Cleaning agent for domestic purpose, , (II) Washing Soda, , (B) Production of Caustic soda, , (III)Bleaching Powder, , (C) Soda-acid fire extinguishers, , (IV) Sodium Chloride, , (D) Oxidizing agent in chemical industries

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a) (I)–(C); (II)–(A); (III)–(D); (IV)–(B), (b) (I)–(B); (II)–(A); (III)–(D); (IV)–(C), (c) (I)–(A); (II)–(C); (III)–(D); (IV)–(B), (d) (I)–(C); (II)–(A); (III)–(B); (IV)–(D), 3. The atomic number of four elements P, Q, R, S are 10, 12, 14 and 16 respectively. The two elements, which can react to form ionic compounds are:, (a) P an S, , (b) Q and R, , (c) P and R, , (d) Q and S, , 4. Identify exothermic reactions from the reactions given below:, (I) Burning of hydrogen gas in air, (II) Heating of calcium carbonate, (III) Photosynthesis, (IV) Respiration, (a) Both (I) and (II), , (b) Both (II) and (IV), , (c) Both (I) and (III), , (d) Both (I) and (IV), , 5. A student performed an activity whose flow chart is shown in the figure below:, , Identify the Gas X, substance Y and observation Z from the table below:, Gas X, , Y, , Z, , (a ), , Dry HCl, , Moist Red litmus paper, , Turns red, , (b), , Dry Cl2, , Moist Red litmus paper, , Turns Blue, , (c), , Dry HCl, , Moist Blue litmus paper, , No Change, , (d), , Dry H2, , Moist Blue litmus paper, , Turns red, , 6. When iron (III) oxide is heated with aluminium powder, then aluminium oxide and iron metal are, formed. Identify the balanced chemical equation for the above reaction:, (a) Fe2O3(s) + Al(s) →Al2O3(s) + 2Fe(l)

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(b) Fe2O3(s) + 2Al(s) →Al2O3(s) + Fe(l), (c) 2Fe2O3(s) + 2Al(s) → Al2O3(s) + 4Fe(l), (d) Fe2O3(s) + 2Al(s) → Al2O3(s) + 2Fe(l), 7. Two glass bottles labelled A and B are taken. Oxalic acid is kept in A and sodium carbonate solution is, kept in B. A strip of universal indicator is dipped in each bottle and colour noted., , Select the row containing the colour shown by bottles A and B on dipping universal indicator strip from the, table below:, A: Oxalic Acid, , B: Sodium carbonate solution, , (a), , Blue, , Orange, , (b), , Blue, , Green, , (c), , Green, , Blue, , (d), , Orange, , Blue, , 8. What is aqua-regia?, (a) It is mixture of conc. HNO3 and H2SO4 (1 : 3), (b) It is a mixture of HCl and HNO3 (3 : 1), (c) It is a mixture of HCl and H2SO4 (3 : 1), (d) It is a mixture of HNO3 and H2SO4 (1 : 3 ), 9. Which of the following reactions are examples of double displacement reactions but not precipitation, reactions?, (I) NaOH + H2SO4 → Na2SO4 + H2O, (II) CuO + 2HCl → CuCl2 + H2O, (III) AlCl3 + 3NH4OH → Al(OH)3 + 3NH4Cl, (IV) CuSO4 + H2S → CuS + H2SO4, (a) Both (I) and (II), , b) Both (I) and (III), , (c) Both (II) and (III), , (d) Both (II) and (IV), , 10. What type of a chemical reaction is represented by the following equation?, 3BaCl2 + Al2(SO4)3 → 2AlCl3 + 3BaSO4, (a) Displacement Reaction, (b) Decomposition Reaction, (c) Precipitation Reaction, (d) Combustion Reaction, 11. The alimentary canal in human beings extends from:

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(a) Small intestine to large intestine, (b) Entire large intestine, (c) Small intestine to anus, (d) Mouth to anus, 12. Study the figure below and identify the parts labelled P, Q and R., , P, , Q, , R, , (a), , Chloroplasts, , Epidermal cells, , Guard cells, , (b), , Guard Cells, , Chloroplasts, , Stomatal pore, , (c), , Stomatal pore, , Upper Epidermis, , Chloroplasts, , (d), , Guard Cells, , Upper Epidermis, , Chloroplasts, , 13. What is the correct path through the circulatory system which describes the passage of blood, originating in the left leg?, (a) Vena cava → left atrium → right atrium → lungs → left ventricle → right ventricle → aorta, (b) Vena cava → right atrium → left atrium → lungs → right ventricle → left ventricle → aorta, (c) Vena cava → left atrium → left ventricle → lungs → right atrium → right ventricle → aorta, (d) Vena cava → right atrium → right ventricle → lungs → left atrium → left ventricle → aorta, 14. The table below lists enzymes and other secretions present in human digestive system in column I and, their function in column II., Column I, , Column II, , (I) Pepsin, , (A)Creates alkaline medium, , (II) Salivary amylase, , (B) Digests Protein, , (III) Bile juice, , (C)Breaks down emulsified fats, , (IV) Lipase, , (D)Breaks down Starch, , Match the contents of column I and II and select the correct option., (a) (I)–(C); (II)–(D); (III)–(A); (IV)–(B), (b) (I)–(B); (II)–(A); (III)–(D); (IV)–(C), (c) (I)–(B); (II)–(D); (III)–(A); (IV)–(C), (d) (I)–(A); (II)–(D); (III)–(B); (IV)–(C), 15. Tracheal rings present in throat ensure that:

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(a) the air-passage must collapse, (b) the air-passage does not collapse, (c) the air-passage does not expand, (d) the food-passage does not collapse, 16. .Roots of the plants absorbs water from the soil through the process of:, (a) Diffusion, , (b) Transpiration, , (c) Osmosis, , (d) Both (a) and (b), , 17. What is the formula for magnification obtained with a lens?, (a) Reciprocal of the radius of curvature of the lens., (b) Ratio of height of object to height of image., (c) Ratio of height of image to height of object., (d) Reciprocal of image distance., 18. A convex lens forms a real image of an object when object is placed at:, (I) Beyond 2F, (II) At Focus F, (III) Between Focus F and Optical Centre O, (IV)Between Focus F and 2F, (a) Both (I) and (II), , (b) Both (II) and (III), , (c) (I), (II) and (IV), , (d) (I), (III) and (IV), , 19. The figure below shows the path of rays A and B incident on an optical component labelled X and, emerging as rays C and D respectively., , The optical component X is a:, (a) concave lens, , (b) convex lens, , (c) convex mirror, , (d) prism, , 20. . The figure below shows position of image A’B’ after reflection from a mirror M., , Identify the type of mirror and select from the table below the row containing correct type of mirror,, position of object and magnification produced above:

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Type of Mirror, , Position of object, , Magnification, , (a), , Convex, , Between C and F, , Greater than - 1, , (b), , Concave, , Between C and F, , Greater than - 1, , (c), , Concave, , Between P and F, , Smaller than - 1, , (d), , Convex, , Anywhere in front of M, , Greater than + 1, , 21. Which of the following graphs shows the correct variation between the power (P) of a converging lens, and its focal length (f)?, , 22. A ray of light passes through a prism as shown in figure: The angle δ is known as:, , (a) angle of emergence (b) angle of dispersion, , (c) angle of prism, , (d) angle of deviation, , 23. Which of the following phenomena contributes significantly to the reddish appearance of the sun at, sunrise or sunset?, (a) Dispersion of light, (b) Scattering of light, (c) Total internal reflection of light, (d) Atmospheric refraction, 24. The colour of sky as seen by an astronaut in space would be black due to:, (a) No scattering of light taking place in space, (b) No atmospheric refraction taking place in space, (c) No dispersion of light taking place in space, (d) Both (b) and (c), SECTION - B, Section B consists of 24 questions (Q. No. 25 to 48). Attempt any 20 questions from this section. The first, attempted 20 questions would be evaluated., 25. A substance P is taken in a china dish and placed in sunlight for some time. It’s colour changes from, white to grey in sunlight.

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Identify the substance P and the type of reaction taking place from the table below:, P, , Type of Reaction, , (a), , AgNO3, , Displacement Reaction, , (b), , AgNO3, , Decomposition Reaction, , (c), , AgCl, , Displacement Reaction, , (d), , AgCl, , Decomposition Reaction, , 26. The organic acid present in tamarind is:, (a) Oxalic acid (b) Tartaric acid, , (c) Citric acid, , (d) Lactic acid, , 27. A compound Z is formed between X and Y, where X loses electron and Y gains electron. Which of the, following properties is not shown by the compound Z?, (a) Has high melting point, (b) Dissolves in solvents such as kerosene and petrol., (c) Conducts electricity in molten state, (d) Occurs as solid, 28. Which of the metals react with dilute Nitric acid and evolve hydrogen gas?, (I) P, , (II) Mg, , (III) Mn, , (IV) Zn, , (a) Both (I) and (II), (b) Both (II) and (III), (c) Both (I) and (IV), (d) Both (II) and (IV), 29. Arrange the following in increasing order of their pH values:, P: NaOH solution, , Q: Blood, , a) R<Q<S <P, , (b) P<Q<R<S, , R: Lemon juice, (c) S<R<Q<P, , S: Milk of magnesia, (d) P<Q<S<R, , 30. Which of the following statement do not correctly represent the use of sodium hydroxide?, (a) It is used in paper making, (b) It is used to rayon and acetate fibers, (c) it is used in killing bacteria in drinking wastes and in swimming pool, (d) It is used in detergents and soaps to remove greases., Question No. 31 to 35 consist of two statements:, Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below: (a), Both A and R are true and R is the correct explanation of A, (b) Both A and R are true and R is not the correct explanation of A, (c) A is true but R is false (d) A is False but R is true

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31. Assertion (A): Gas bubbles are observed when sodium carbonate is added to dilute hydrochloric acid., Reason (R): Carbon dioxide is given off in the reaction, 32. Assertion (A): Salts of strong acids and weak bases are basic in nature., Reason (R): pH value of basic salt is more than 7., 33. Assertion (A): Ionic compounds in the solid state do not conduct electricity., Reason(R): Ionic compounds conduct electricity in the molten state., 34. Assertion (A): Carbohydrate digestion mainly takes place in small intestine., Reason (R): Pancreatic juice contains the enzyme lactase., 35. Assertion (A): A rainbow is a natural spectrum appearing in the sky after a rain shower., Reason (R): It is caused by reflection of sunlight by tiny water droplets present in the atmosphere, 36. Given below are four statements regarding the reaction of calcium with water?, (I) It does not react with cold water., (II) It reacts violently with cold water., (III) Calcium starts floating as the bubbles of hydrogen gas formed stick to the surface of calcium., (IV)The hydrogen gas evolved immediately catches fire., Select the incorrect statements:, (a) Both (I) and (II), (b) Both (II) and (III), (c) (II), (III) and (IV), (d) (I), (II) and (IV), 37. Select the pair showing incorrect function of the parts of nephron in kidneys:, (a) Bowman’s capsule: Collects filtrate, (b) Tubule: Reabsorbs useful substances, (c) Ureter: Transports urine from kidney to urethra, (d) Urinary bladder: Stores urine, 38. Study the graph below that represents the blood test reports of an athlete just before and after a race., , Choose the correct combination of plots provided in the following table., Section of race, , Change in concentration of lactic, , Type of respiration taking place, , acid, (a), , A–B, , High to low, , Anaerobic to aerobic, , (b), , B–C, , Remains constant, , Aerobic to anaerobic, , (c), , C–D, , Low to high, , Anaerobic to aerobic, , (d), , D-E, , High to low, , Anaerobic to aerobic

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39. An object is placed 27 cm in front of a concave mirror of focal length18 cm. Select the row containing, the correct values of image distance, nature of image formed and magnification from the table given below:, Image distance, , Nature of image, , Magnification, , (a), , – 54 cm, , Virtual, erect, magnified, , –2, , (b), , – 54 cm, , Real, inverted, magnified, , –2, , (c), , + 54 cm, , Virtual, erect, magnified, , +2, , (d), , – 27 cm, , Real, inverted, same size as object, , –1, , 40. If the absolute refractive in dices for water and diamond are1.33 and 2.4 respectively, then the, refractive index of diamond relative to water is:, (a) 0.55, , (b) 1.80, , (c) 3.19, , (d) 0.90, , 41. The function of villi present on the internal wall of intestine is:, (a) Emulsification of fats, (b) Breakdown of proteins, (c) Absorption of digested food, (d) Digestion of carbohydrates, 42. Which of the following is NOT a purpose of transpiration?, (a) Helps in absorption and upward movement of water, (b) Helps in translocation of sugar in plants, (c) Helps in temperature regulation, (d) Helps in transporting minerals from roots to leaves., 43. Velocity of light in air is 3.0 × 108 m/s while its velocity in a medium ‘X’ is 1.8 × 108 m/s. The, refractive index of medium ‘X’ is:, (a) 1.8, , (b) 0.6, , (c) 1.67, , (d) 2.0, , 44. A candle placed 25 cm in front of a lens forms an image on a screen placed at 75 cm on the other side, of the lens. The focal length and type of the lens should be:, Type of lens, , Focal length, , (a), , Convex Lens, , + 18.75 cm, , (b), , Convex Lens, , + 37.5 cm, , (c), , Concave lens, , – 18.75 cm, , (d), , Concave lens, , – 37.5 cm, , 45. The magnification produced by a plane mirror is:, (a) Between 0 and +1, , (b) + 1, , (c) – 1, , (d) 0, , 46. White light incident at an angle to the surface of a triangular piece of glass. Which colour of light least, deviates from its original path after leaving the glass?, (a) Red, , (b) Blue, , (c) Green, , (d) Violet, , 47. The given diagram shows the dispersion of the white light in the prism. What will be the colours of the, X, Y and Z?

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(a) X: red; Y: green; Z: violet, (b) X: violet; Y: green; Z: red, (c) X: green; Y: violet; Z: red, (d) X: red; Y: violet; Z: green, 48. Samples of silver, copper, PVC and graphite were taken and placed one by one between the terminals, A and B as shown:, , The bulb does not glow after inserting which of the substances?, (I) PVC, (a) Only (I), , (II) Graphite, (b) Only (II), , (III) Silver, , (c) Both (I) and (III), , (IV) Copper, , (d) Both (II) and (IV), , SECTION – C, (Section C consists of three Cases followed by questions. There are a total of 12 questions in this section., Attempt any 10 questions from this section. The first attempted 10 questions would be evaluated.), Q. 49 to 52 are based on Case Study, Case 1: A chemical equation is the representation of chemical change in terms of symbols and formulae of, reactants and products. The substances which react are written on the left hand side of the arrow and are, termed as reactants while the substances produced as result of reaction are called products and are written, on the right hand side of the arrow. The arrowhead shows the direction of the reaction. A chemical, equation in which the number of atoms of each element on reactant side is equal to that on the product side, is said to be balanced. A chemical equation should include all the information regarding the reaction-it, should represent a true chemical change, it should be balanced, it should be molecular and it should, represent the change in temperature.

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49. Which of the following are NOT redox reactions?, (a) CaO + SiO2 → CaSiO3, (b) Fe + H2SO4 → FeSO4 + H2, (c) H2S + Cl2 → S + 2HCl, (d) H2S + I2 → 2HI + S, 50. Among the following, the correct balanced equation is, (a) 3Fe + 4H2O → Fe3O4 + 4H2, (b) Zn + HCl → ZnCl2 + H2, (c) N2 + H2 → NH3, (d) C + O2 → CO, 51. In which of the following equation, the mass is not same on both the sides?, (a) Word equation, (b) Skeletal equation, (c) Balanced equation, (d) Both (a) and (b), 52. Select the combination reaction, (a) C + O2 →CO2, (b) Ca + H2O →Ca (OH)2, (c) 2H2 + O2→ 2H2O, (d) All of these, Case 2: Humans have an efficient system to transport substances from organs to the cells that use them., Blood can transport most substances and is moved around the body by the circulatory system. Humans, have a double circulatory system. The heart pumps blood through two circuits: (I) the pulmonary, circulation (II) the systemic circulation.

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Blood pressure is the force of your blood pushing against the walls of your arteries. Each time your heart, beats, it pumps blood into the arteries. Your blood pressure is highest when your heart beats, pumping the, blood. This is called systolic pressure. When your heart is at rest, between beats, your blood pressure falls., This is called diastolic pressure., 53. The normal diastolic blood pressure in a normal healthy adult human is:, (a) 80 mm Hg, , (b) 60 mm Hg, , (c) 90 mm Hg, , (d) 120 mm Hg, , 54. The thickness of blood capillaries is:, (a) 1 cell thick (b) 10 Cells Thick, , (c) 100 Cells Thick, , (d) 100,000 Cells thick, , 55. A student analysed the above graph and noted the following observations: Select the incorrect, statement (s):, , (I) Arteries carry blood away from the heart to different body organs, (II) Arteries have thin, elastic walls., (III) Veins collect blood from different body organs and bring it back to heart., (IV)Veins have thick walls., (a) Both (I) and (II), (b) Both (II) and (IV), (c) Both (I) and (III), (d) Both (II) and (III), 56. The above graph shows the variation of average pressure exerted by blood as blood flows in the body., (I) The force exerted by blood on walls of arteries is greater than in veins., (II) The force exerted by blood on walls of veins is greater than in arteries., (III) Systolic pressure is the pressure of blood in the artery during contraction of ventricles., (IV)Diastolic pressure is the pressure of blood in the veins during relaxation of ventricles., (a) Only (I), (b) Both (II) and (III), (c) Both (I) and (III), (d) Both (II) and (IV), Case: 3 The Tyndall effect is the phenomenon in which the particles in a colloid scatter the beams of light, that are directed at them. This effect is exhibited by all colloidal solutions and some very fine suspensions.

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Therefore, it can be used to verify if a given solution is a colloid. The intensity of scattered light depends, on the density of the colloidal particles as well as the frequency of the incident light. When a beam of light, passes through a colloid, the colloidal particles present in the solution do not allow the beam to completely, pass through. The light collides with the colloidal particles and is scattered (it deviates from its normal, trajectory, which is a straight line). This scattering makes the path of the light beam visible, as illustrated, below, , 57. Tyndall effect is due to :, (a) Scattering of light (b) dispersion of light, , (c) reflection of light, , 58. A star appears twinkling in the sky because of:, (a) scattering of light by atmosphere, (b) reflection of light by atmosphere, (c) refraction of light by atmosphere, (d) diffraction of light by atmosphere, 59. Which colour of light scatters maximum due to atmosphere?, (a) Blue, , (b) Yellow, , (c) Green, , (d) Red, , 60. Bigger size particles present in atmosphere scatter the light of?, (a) smaller wavelength, (b) medium wavelength, (c) larger wavelength, (d) only blue colour., *************, , (d) refraction of light