CBSE Class 10 Science 2024 — Set 3

Questions in this 2024 Science paper (Set 3)

All 39 questions from this set, exactly as asked. Try each one, then open the question-paper PDF above for the complete paper.

1. 1.
   Identify the product 'X' obtained in the following chemical reaction: CaCO₃ →(Δ) 'X' + CO₂

   • (a) Quick lime
   • (b) Gypsum
   • (c) Lime Stone
   • (d) Plaster of Paris
2. 2.
   Select a pair of natural indicator from the following:

   • (a) Litmus and methyl orange
   • (b) Turmeric and Litmus
   • (c) Phenolphthalein and methyl orange
   • (d) Methyl orange and Turmeric
3. 3.
   A chemical compound used in glass, soap and paper industries is:

   • (a) Washing Soda
   • (b) Baking Soda
   • (c) Bleaching Powder
   • (d) Common Salt
4. 4.
   The structural formula of Cyclohexane is:

   • (a) A benzene-like ring structure with alternating double bonds and H atoms on each carbon (incorrect — this is benzene)
   • (b) A six-membered ring with all single bonds, each carbon bonded to two H atoms (chair/ring form of cyclohexane)
   • (c) A ring structure with triple bonds between carbons
   • (d) A six-membered ring with alternating double bonds and single H…
5. 5.
   Consider the following Chemical equation: a Al₂O₃ + b HCl → c AlCl₃ + d H₂O In order to balance this chemical equation, the values of a, b, c and d must be:

   • (a) 1, 6, 2 and 3
   • (b) 1, 6, 3 and 2
   • (c) 2, 6, 2 and 3
   • (d) 2, 6, 3 and 2
6. 6.
   Which one of the following hydrocarbons is different from the others?

   • (a) C₄H₁₀
   • (b) C₇H₁₄
   • (c) C₅H₁₂
   • (d) C₂H₆
7. 7.
   Which one of the following reactions is different from the remaining three? (A) NaCl + AgNO₃ → AgCl + NaNO₃ (B) CaO + H₂O → Ca(OH)₂ (C) KNO₃ + H₂SO₄ → KHSO₄ + HNO₃ (D) ZnCl₂ + H₂S → ZnS + 2HCl

   • (a) NaCl + AgNO₃ → AgCl + NaNO₃
   • (b) CaO + H₂O → Ca(OH)₂
   • (c) KNO₃ + H₂SO₄ → KHSO₄ + HNO₃
   • (d) ZnCl₂ + H₂S → ZnS + 2HCl
8. 8.
   Select from the following a plant hormone which promotes cell division.

   • (a) Gibberellins
   • (b) Auxins
   • (c) Abscissic Acid
   • (d) Cytokinins
9. 9.
   Part(s) of a flower which attracts insects for pollination is (are):

   • (a) petals and Sepals
   • (b) anther and Stigma
   • (c) petals only
   • (d) sepals only
10. 10.
    In an experiment to study independent inheritance of two separate traits: shape and colour of seeds, the ratio of the different combinations in F₂ progeny would be:

    • (a) 1 : 3
    • (b) 1 : 2 : 1
    • (c) 9 : 3 : 3 : 1
    • (d) 9 : 1 : 1 : 3
11. 11.
    Which of the following statement(s) is (are) true about human heart?

    • (a) Right atrium receives oxygenated blood from lungs through pulmonary artery.
    • (b) Left atrium transfers oxygenated blood to left ventricle which sends it to various parts of the body.
    • (c) Right atrium receives deoxygenated blood from different parts of the body through vena cava.
    • (d) Left atrium transfers oxygenated blood to…
12. 12.
    A cross between two tall pea plants resulted in offsprings having a few dwarf plants. The gene-combination of the parental plants must be:

    • (a) Tt and Tt
    • (b) Tt and tt
    • (c) TT and tt
    • (d) TT and Tt
13. 13.
    The Phenomena of light involved in the formation of a rainbow in the sky are:

    • (a) Refraction, dispersion and reflection
    • (b) Refraction, dispersion and total internal reflection
    • (c) Dispersion, scattering and reflection
    • (d) Dispersion, refraction and internal reflection
14. 14.
    In case of four wires of same material, the resistance will be minimum if the diameter and length of the wire respectively are:

    • (a) D/2 and L/4
    • (b) D/4 and 4L
    • (c) 2D and L
    • (d) 4D and 2L
15. 15.
    A food chain will be more advantageous in terms of energy if it has:

    • (a) 2 trophic levels
    • (b) 3 trophic levels
    • (c) 4 trophic levels
    • (d) 5 trophic levels
16. 16.
    Consider the following statements about ozone:

    • (a) Ozone is poisonous gas.
    • (b) Ozone shields the earth's surface from the infrared radiation from the sun.
    • (c) Ozone is a product of UV radiations acting on oxygen molecule.
    • (d) At the lower level of the earth's atmosphere, ozone performs most essential function. The correct statements are:
    • (a) (a) and
    • (b) (b)
    • (a) and
    • (c) (c)
    • (b) and
    • (c) (d) (b)…
17. 17.
    Assertion (A): A piece of Zinc metal gets reddish brown coating when kept in copper sulphate solution for some time. Reason (R): Copper is more reactive metal than Zinc. (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 correct explanation of (A). (C) (A) is true, but (R) is false. (D) (A) is false, but (R) is true. (a) Both (A)…
18. 18.
    Assertion (A): Offsprings produced by asexual reproduction are genetically similar to the parents. Reason (R): Asexual reproduction involves a single parent. (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 correct explanation of (A). (C) (A) is true, but (R) is false. (D) (A) is false, but (R) is true. (a) Both (A) and (R) are…
19. 19.
    Assertion (A): Red light signals are used to stop the vehicles on the road. Reason (R): Red coloured light is scattered the most so as to be visible from a large distance. (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 correct explanation of (A). (C) (A) is true, but (R) is false. (D) (A) is false, but (R) is true. (a) Both…
20. 20.
    Assertion (A): The waste we generate daily may be biodegradable or non-biodegradable. Reason (R): The waste generated, if not disposed off properly may cause serious environmental problems. (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 correct explanation of (A). (C) (A) is true, but (R) is false. (D) (A) is false, but (R)…
21. 21.
    When magnesium ribbon is burnt in air, an ash of white colour is produced. Write chemical equation for the reaction giving the chemical name of the ash produced. State the type of chemical reaction giving justification for your answer.
22. 22.
    Where are auxins synthesized? How do they promote phototropism?
23. 23.
    List any two pairs of visible contrasting characters of garden pea plants used by Mendel for his experiments stating the dominant and recessive characters in each pair. OR (b) In human beings, the probability of getting a male or a female child is 50%. Explain with the help of a flow diagram only.
24. 24.
    When do we say that a particular person is suffering from hypermetropia? List two causes of this defect. Name the type of lens used to correct this defect.
25. 25.
    Draw a labelled diagram to show the pattern of magnetic field lines produced due to a current carrying straight conductor. Mark on it the direction of current in the conductor and the direction of magnetic field lines. OR (b) Name the device used to magnetise a piece of magnetic material. Draw a labelled diagram to show the arrangement used for the magnetisation of a cylinder made of soft iron.
26. 26.
    What are decomposers? List two consequences of their absence in an ecosystem.
27. 27.
    State reasons for the following:

    • (a) Zinc oxide is an amphoteric oxide.
    • (b) Sodium metal is stored in bottle filled with kerosene oil.
    • (c) In the reactions of nitric acid with metals, generally hydrogen gas is not evolved.
28. 28.
    State giving reason the reduction process to obtain the following metals from their compounds:

    • (i) Mercury
    • (ii) Copper
    • (iii) Sodium OR
    • (b) State giving reason for the change in appearance observed when each of the following metal is exposed to atmospheric air for some time:
    • (i) Silver
    • (ii) Copper
    • (iii) Iron
29. 29.
    We water the soil but it reaches the topmost leaves of the plants. Explain in brief the process involved.
30. 30.
    List two constituents of Central Nervous System (CNS). How are these components protected from injuries? (b) Write two limitations of the use of electrical impulses.
31. 31.
    Name and explain the phenomenon of light due to which the path of a beam of light becomes visible when it enters a smoke filled room through a small hole. Also state the dependence of colour of the light we receive on the size of the particle of the medium through which the beam of light passes.
32. 32.
    Explain in brief the function of an electric fuse in a domestic circuit. An electric heater of current rating 3 kW; 220 V is to be operated in an electric circuit of rating 5 A. What is likely to happen when the heater is switched 'ON'? Justify your answer with necessary calculation.
33. 33.
    State Ohm's law. Write formula for the equivalent resistance R_p of the parallel combination of three resistors of values R₁, R₂ and R₃. (b) Find the resistance of the following network of resistors: [A circuit diagram showing three resistors, each of resistance R: one in series on top, and two in parallel (one on top, one on bottom) between points X and Y]
34. 34.
    • (i) Five solutions A, B, C, D and E when tested with pH paper showed pH as 4, 1, 13, 7 and 10 respectively. Which solution is: (1) Strongly acidic (2) Strongly alkaline (3) Weakly acidic (4) Neutral and (5) Weakly alkaline? Arrange the solutions in increasing order of H⁺ ion concentration.
    • (ii) Write the name and formula of (1) an acidic salt and (2) a basic salt, giving the name of the parent…
35. 35.
    • (i) What are spores? On which structures are they formed? How do they overcome unfavourable conditions? Name the organism which multiplies with the help of these structures.
    • (ii) Give two reasons why some plants are grown by the method of vegetative propagation. List two methods used to grow plants vegetatively. OR
    • (b) (i) Study the diagram given below and name the parts marked as A, B and C…
36. 36.
    • (i) Draw a ray diagram to show the path of the refracted ray in each of the following cases: A ray of light incident on a concave lens (1) parallel to its principal axis, and (2) is directed towards its principal focus.
    • (ii) A 4 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 24 cm. The distance of object from the lens is 16 cm. Find the position and…
37. 37.
    Case Study: More than three million carbon compounds have been discovered in the field of chemistry. The diversity of these compounds is due to the capacity of carbon atoms for bonding with one another as well as with other atoms. Most of the carbon compounds are poor conductors of electricity and have low melting and boiling points.
38. 37 (a).
    (Case Study Q37) Write the molecular formula of first two members of homologous series having functional group –Br.
39. 37 (b).
    (Case Study Q37) Given below are the formulae of some functional groups:

    • (i) –C(=O)–H
    • (ii) –C(=O)– Write the name of these functional groups.
40. 37 (c).
    (Case Study Q37)

    • (i) What would be observed on adding a 5% alkaline potassium permanganate drop by drop to some warm ethanol taken in a test tube? State the role of KMnO₄ in the reaction and write the chemical equation for the reaction involved. OR
    • (ii) Write the name of the compound formed when ethanol is heated at 443 K temperature with excess of conc. H₂SO₄. What is the role of conc. H₂SO₄ in…
41. 38.
    Case Study: Human digestive system is a tube running from mouth to anus. Its main function is to breakdown complex molecules present in the food which cannot be absorbed as such into smaller molecules. These molecules are absorbed across the walls of the tube and the absorbed food reaches each and every cell of the body where it is utilised for obtaining energy.
42. 38 (a).
    (Case Study Q38) Name the glands present in the buccal cavity and write the components of food on which the secretion of these glands act upon.
43. 38 (b).
    (Case Study Q38) Two organs have a sphincter muscle at their exit. Name them.
44. 38 (c).
    (Case Study Q38) What will happen if:

    • (i) mucus is not secreted by the gastric glands.
    • (ii) Villi are absent in the small intestine. OR "Bile juice does not contain any enzyme, yet it has important roles in digestion." Justify the statement.
45. 39.
    Case Study: In a domestic circuit five LED bulbs are arranged as shown. The source voltage is 220 V and the power rating of each bulb is marked in the circuit diagram. Based on the following circuit diagram, answer the following questions: [Circuit diagram shows: Bulb A (22W, 220V) in series with the mains. After bulb A, the circuit splits into two parallel branches controlled by keys K₁ and K₂…
46. 39 (a).
    (Case Study Q39) State what happens when:

    • (i) key K₁ is closed.
    • (ii) key K₂ is closed.
47. 39 (b).
    (Case Study Q39) Find the current drawn by the bulb B when it glows.
48. 39 (c).
    (Case Study Q39) Calculate:

    • (i) the resistance of bulb B, and
    • (ii) total resistance of the combination of four bulbs B, C, D and E. OR What would happen to the glow of all the bulbs in the circuit when keys K₁ and K₂ both are closed and the bulb C suddenly get fused? Give reason to justify your answer.

Class 10 Science exam pattern (80 marks)

The theory paper carries 80 marks over 3 hours (39 questions, with internal choice in some). Section-wise structure:

Structure per the CBSE 2023-24 sample-paper design; question wording varies by set.

Prepare with

How to use these papers

1. 1Start chapter-wise early in the year — solve only the Science questions from a chapter you have just finished.
2. 2Switch to full timed papers 2–3 months before the exam: one complete set in the real time limit, no notes.
3. 3Self-mark against the marking scheme, then fix every mistake with our free NCERT solutions.
4. 4Re-attempt your weakest chapters until the recurring question types feel routine.

CBSE Class 10 Science 2024 paper — FAQ