CBSE Class 10 Science 2025 — Set 3

Questions in this 2025 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.
   Consider the following chemical equation: pAl + qH₂O → rAl₂O₃ + sH₂ To balance this chemical equation, the values of p, q, r and s must be respectively:

   • (a) 3, 2, 2, 1
   • (b) 2, 3, 1, 1
   • (c) 2, 3, 1, 3
   • (d) 3, 1, 2, 3
2. 2.
   Which of the given option represents a family of salts?

   • (a) NaCl, Na₂SO₄, CaSO₄
   • (b) NaNO₃, CuSO₄, CaCO₃
   • (c) K₂SO₄, Na₂SO₄, CaSO₄
   • (d) MgCO₃, CaSO₄, MgCl₂
3. 3.
   The most common method of extraction of metals from their oxide ores is:

   • (a) Reduction with carbon
   • (b) Reduction with hydrogen
   • (c) Reduction with aluminium
   • (d) Electrolytic reduction
4. 4.
   Given below are the structures of some hydrocarbons. Select the two structures which are related to each other from the given options:

   • (i) H-C(H₂)-C(H₂)-C=C-H (with H atoms, C₄H₈ - butene)
   • (ii) H-C(H₂)-C(H₂)-C(H₂)-C(H₂)-H (pentane, C₅H₁₂)
   • (iii) H-C(H₂)-C(H)(CH₂)-C(H₂)-H (branched, isobutane/2-methylpropane)
   • (iv) Cl-C(H₂)-C(H₂)-C=C-H (chloro-substituted butene)
   • (a) (i) and
   • (iv) (b)
   • (ii) and (iv)…
5. 5.
   Choose the incorrect statement about the common reaction used in hydrogenation of vegetable oils.

   • (a) It is an addition reaction.
   • (b) It takes place in the presence of nickel or palladium catalyst.
   • (c) The product contains only single bonds between carbon atoms.
   • (d) It is an addition reaction which occurs in the presence of an acid catalyst.
6. 6.
   Match Column-I with Column-II and select the correct option: Column-I: a. Site of fertilisation of egg with the sperm b. Site of implantation of embryo c. Site of entry of sperm into the female reproductive tract d. Site through which the waste materials generated by the developing embryo are removed Column-II:

   • (i) Vagina
   • (ii) Uterus
   • (iii) Oviduct
   • (iv) Placenta
   • (v) Cervix
   • (a) a-(ii), b-(i)…
7. 7.
   The part of the brain that maintains the posture and balance of the body is:

   • (a) Pons
   • (b) Cerebrum
   • (c) Cerebellum
   • (d) Medulla
8. 8.
   The plant hormone present in greater concentration in the areas of rapidly dividing cells is:

   • (a) Auxin
   • (b) Cytokinins
   • (c) Gibberelline
   • (d) Abscisic acid
9. 9.
   Select a pair of bisexual flowers from the following:

   • (a) Papaya and mustard
   • (b) Hibiscus and mustard
   • (c) Hibiscus and papaya
   • (d) Hibiscus and watermelon
10. 10.
    The gastric glands present in the wall of the stomach release:

    • (a) Mucus and Trypsin
    • (b) Pepsin and Trypsin
    • (c) Mucus and Pepsin
    • (d) Pepsin and Salivary amylase
11. 11.
    Absolute refractive index of water and glass is 4/3 and 3/2 respectively. If the speed of light in glass is 2 × 10⁸ m/s, the speed of light in water is:

    • (a) 8/3 m/s
    • (b) 3 m/s
    • (c) 10/3 m/s
    • (d) 9/4 m/s
12. 12.
    When a beam of white light passes through a region of very fine dust particles, the colour of light that scatters the most in that region is:

    • (a) red
    • (b) orange
    • (c) blue
    • (d) yellow
13. 13.
    A wire of length 'l' is gradually stretched so that its length increases to 3l. If its original resistance is R, then its new resistance will be:

    • (a) 3R
    • (b) 6R
    • (c) 9R
    • (d) 27R
14. 14.
    Which one of the following statements is not true about a bar magnet?

    • (a) It sets itself in north-south direction when suspended freely.
    • (b) It has attractive power for iron filings.
    • (c) It produces magnetic field lines.
    • (d) The direction of magnetic field lines inside a bar magnet is from its north pole to its south pole.
15. 15.
    The strength of magnetic field produced inside a long straight current carrying solenoid does not depend upon:

    • (a) number of turns in the solenoid
    • (b) direction of current flowing through the solenoid
    • (c) material of the core filled inside the solenoid
    • (d) radius of the coil of the solenoid
16. 16.
    Other than the abiotic components, which of the given biotic components are not required to make an aquarium with small herbivorous fishes a self-sustaining system?

    • (i) Aquatic plants and aquatic animals
    • (ii) Terrestrial plants and terrestrial animals
    • (iii) Decomposers as bacteria and fungi
    • (iv) Consumers as clown fishes and sea urchins
    • (a) (i) and
    • (iv) (b)
    • (ii) and
    • (iii) (c)
    • (i) and
    • (iii) (d)…
17. 17.
    For Questions 17 to 20, two statements are given - one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer from the codes (A), (B), (C) and (D). Assertion (A): Hydrogen gas is not evolved when a metal reacts with nitric acid. Reason (R): Nitric acid is a strong reducing agent and reduces the hydrogen produced in the reaction to water. (a) Both Assertion (A)…
18. 18.
    Assertion (A): In our actions of writing or talking, our nervous system communicates with the muscles. Reason (R): Cranial nerves and spinal nerves form the peripheral nervous system.

    • (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
    • (b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion…
19. 19.
    Assertion (A): Magnetic field lines around a bar magnet never intersect each other. Reason (R): Magnetic field produced by a bar magnet is a quantity that has both magnitude and direction.

    • (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
    • (b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of…
20. 20.
    Assertion (A): Use of jute bags for shopping reduces pollution. Reason (R): Jute is biodegradable and its bag may be reused as and when required.

    • (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
    • (b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
    • (c) Assertion (A) is true, but…
21. 21.
    List the possible sources of energy required in decomposition reactions. Illustrate any one with a suitable example. OR (b) What is observed when hydrated ferrous sulphate crystals are heated in a dry boiling tube? Give balanced chemical equation(s) of the reaction(s) that occur(s).
22. 22.
    Write the formula of the ions which

    • (i) acids, and
    • (ii) bases generate in water solutions.
    • (b) Dry HCl gas does not change the colour of dry litmus paper. Why?
23. 23.
    State the main functions of veins in human circulatory system. Why do they not need thick walls?
24. 24.
    Explain how the proteins control the 'characteristics' in an organism with the help of an example of 'tallness' trait in pea plant. (b) Name the section of DNA that controls the 'characteristics' in an organism.
25. 25.
    A student has difficulty in reading his textbooks but can read the blackboard clearly while sitting in the last row. Name the defect of vision the student is suffering from. List two reasons due to which this defect arises. Write the nature of the lenses required to correct this defect. OR (b) Draw a ray diagram to show the path of a ray of light falling obliquely on one of the refracting faces…
26. 26.
    An electric kettle is rated 230 V, 1000 W. Calculate the resistance of its heating element when in operation.
27. 27.
    What is a reactivity series of elements? How is it developed? Arrange the following elements as they are arranged in the reactivity series: Aluminium, Calcium, Copper, Lead. (b) Write balanced chemical equation to show the reaction of iron (III) oxide (Fe₂O₃) with aluminium.
28. 28.
    Common salt is an important raw material for various chemicals of daily use. State in brief the method of preparation of

    • (i) Sodium hydroxide, and
    • (ii) Sodium hydrogen carbonate from common salt. Write balanced chemical equations of the reactions that occur. OR
    • (b) Design an experimental set-up to demonstrate that 'Alcohol and glucose contain hydrogen but are not categorised as acids'. Also give…
29. 29.
    On the basis of the characteristics of the processes given in the brackets in each case, differentiate between the following:

    • (a) Production or breakdown of pyruvate in aerobic and anaerobic respiration in human beings (product(s) of the processes)
    • (b) Respiration and photosynthesis in plants (gas released)
    • (c) Respiration in terrestrial animals and fishes (organs involved)
30. 30.
    A pure pea plant having round (R), yellow (Y) seeds is crossed with another pure pea plant having wrinkled (r), green (y) seeds. Subsequently F₁ progeny is self-pollinated to obtain F₂ progeny. (a) What do the seeds of F₁ generation look like? (b) Give the possible combinations of traits in seeds of F₂ generation. Also give their ratio. (c) State the reason of obtaining seeds of new combination…
31. 31.
    What is a rainbow? Draw a labelled diagram to show its formation.
32. 32.
    Consider a rectangular cardboard having two holes P and Q through which a current carrying circular loop has been inserted as shown in the diagram.

    • (a) Make this diagram on your answer sheet and draw three magnetic field lines, one each passing through the points 1 (near P), 2 (at the centre of the loop) and 3 (near Q).
    • (b) List two factors on which the intensity of the magnetic field produced…
33. 33.
    "In a food chain energy flow is unidirectional." Give two reasons for the given statement. (b) If 10,000 J energy is available at the producer level, how much energy will be available to the secondary consumers? Give reason to justify your answer.
34. 34.
    (i) Consider the following metals: K, Ca, Al, Cu, Ag, Fe. Select from the above metals, a metal which: I. does not react with oxygen even at high temperature. II. reacts at ordinary temperature and forms a protective oxide layer which prevents the metal from further oxidation. III. catches fire when kept in the open. IV. does not burn in oxygen but the hot metal is coated with a black coloured…
35. 35.
    • (i) Identify the parts 'X' and 'Y' in the figure of a flower given below (showing petals, sepals, and reproductive parts marked X and Y).
    • (ii) Name the yellowish coloured structures produced by the part labelled as 'Y'.
    • (iii) Write the name of the process by which these are transferred to the part labelled as 'X'.
    • (iv) Explain the process of seed formation in a flowering plant. OR
    • (b) (i) Name…
36. 36.
    • (i) 'In refraction of light through a rectangular glass slab, the emergent ray is always parallel to the direction of the incident ray.' Why? Explain with the help of a ray diagram. What happens when a ray of light falls normally on one of the faces of a rectangular glass prism? Draw diagram.
    • (ii) An object is placed at a distance of 30 cm from the optical centre of a concave lens of focal…
37. 37.
    Case Study: 'A' and 'B' are two salts used for washing purposes. Salt 'A' is used for bathing also. Four test tubes I, II, III and IV as mentioned below are taken. I. Rain water + solution of salt 'A' II. Rain water + solution of salt 'B' III. Tubewell water + solution of salt 'A' IV. Tubewell water + solution of salt 'B' All the test tubes are shaken well. A permanent lather/foam is formed in…
38. 37 (a).
    Q37(a): From the case study about salts A and B used for washing, where lather forms in test tubes I and II (rain water) but not in III and IV (tubewell water): What type of water is rain water? Name any two salts dissolved in tubewell water that make it different from rain water.
39. 37 (b).
    Q37(b): Why does permanent lather form in test tubes I and II but not in III and IV?
40. 37 (c).
    Q37(c): Which salt out of 'A' and 'B' is a soap? What is the other salt called? Justify your answer.
41. 38.
    Case Study: In the given circuit diagram, two resistors of resistances R₁ and R₂ are shown. A student performed four arrangements as follows: Arrangement No. 1 - only resistor R₁ in gap XY Arrangement No. 2 - only resistor R₂ in gap XY Arrangement No. 3 - Resistors R₁ and R₂ in series in gap XY Arrangement No. 4 - Resistors R₁ and R₂ in parallel in gap XY Voltmeter and ammeter readings were…
42. 38 (a).
    Q38(a): From the V-I graphs (where D is steepest, then C, B, A), which one of the graphs represents the series combination of R₁ and R₂?
43. 38 (b).
    Q38(b): From the V-I graphs, which one of the graphs represents the parallel combination of R₁ and R₂?
44. 38 (c).
    Q38(c)(i): Show an arrangement of three resistors, each of resistance 10 Ω, so that the combination has a resistance of 15 Ω. Give justification for your answer. OR Q38(c)(ii): A battery of 6 V is connected with a series combination of five resistors of 0.1 Ω, 0.2 Ω, 0.3 Ω, 0.4 Ω and 0.5 Ω. How much current would flow through the 0.3 Ω resistor? Justify your answer.
45. 39.
    Case Study: A person while climbing up a rocky hill comes into a panic state and fear. His body starts reacting in a 'fight or flight' condition to adapt to the dangerous and stressful situation. Based on the above facts, answer the following questions.
46. 39 (a).
    Q39(a): Name the hormone secreted in the blood of the person in the fight-or-flight situation. Name the source gland of this hormone.
47. 39 (b).
    Q39(b): State any two responses in the body of the person as a result of the secretion of this hormone. OR Q39(b) OR: How does the action of the chemical signal in terms of hormones differ from the electrical impulses via nerve cells?

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 2025 paper — FAQ