CBSE Class 10 Science 2023 — Set 6

Questions in this 2023 Science paper (Set 6)

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.
   Metal oxides generally react with acids, but few oxides of metal also react with bases. Such metallic oxides are: I. MgO II. ZnO III. Al₂O₃ IV. CaO

   • (a) I and II
   • (b) II and III
   • (c) III and IV
   • (d) I and IV
2. 2.
   Few drops of aqueous solution of ammonium chloride are put on a universal indicator paper. The paper turns pink. Study the following table and choose the correct option. Nature | Ammonium chloride is a salt of .... | Range of pH

   • (a) Acidic; weak acid and strong base; less than 7
   • (b) Basic; weak acid and strong base; more than 7
   • (c) Acidic; strong acid and weak base; less than 7
   • (d) Basic; strong…
3. 3.
   Select the appropriate state symbols of the products given as X and Y in the following chemical equation by choosing the correct option from the table given below: Zn(s) + H₂SO₄(l) → ZnSO₄(X) + H₂(Y) (X) (Y)

   • (a) (s) and
   • (l) (b) (aq) and
   • (g) (c) (aq) and
   • (s) (d)
   • (g) and (aq)
4. 4.
   Two salts 'X' and 'Y' are dissolved in water separately. When phenolphthalein is added to these two solutions, the solution 'X' turns pink and the solution 'Y' does not show any change in colour, therefore 'X' and 'Y' are: (X) (Y)

   • (a) Na₂CO₃ and NH₄Cl
   • (b) Na₂SO₄ and NaHCO₃
   • (c) NH₄Cl and Na₂SO₄
   • (d) NaNO₃ and Na₂SO₄
5. 5.
   In the given diagram of a closed stomata, (1), (2), (3) and (4) respectively are:

   • (a) Nucleus, Chloroplast, Guard cell, Vacuole
   • (b) Nucleus, Chloroplast, Vacuole, Guard cell
   • (c) Chloroplast, Nucleus, Vacuole, Guard cell
   • (d) Vacuole, Guard cell, Nucleus, Chloroplast
6. 6.
   Walking in a straight line and riding a bicycle are the activities which are possible due to a part of the brain. Choose the correct location and name of this part from the given table: Part of the Brain | Name

   • (a) Fore brain — Cerebrum
   • (b) Mid brain — Hypothalamus
   • (c) Hind brain — Cerebellum
   • (d) Hind brain — Medulla
7. 7.
   A student wants to obtain an erect image of an object using a concave mirror of 10 cm focal length. What will be the distance of the object from mirror?

   • (a) Less than 10 cm
   • (b) 10 cm
   • (c) Between 10 cm and 20 cm
   • (d) More than 20 cm
8. 8.
   Bronze is an alloy of:

   • (a) Copper and Zinc
   • (b) Aluminium and Tin
   • (c) Copper, Tin and Zinc
   • (d) Copper and Tin
9. 9.
   In an experiment with pea plants, a pure tall plant (TT) is crossed with a pure short plant (tt). The ratio of pure tall plants to pure short plants in F₂ generation will be:

   • (a) 1 : 3
   • (b) 3 : 1
   • (c) 1 : 1
   • (d) 2 : 1
10. 10.
    Study the given figure of a Food web and identify the primary consumer in the food web: [Food web shows: Seeds, Plants, Grass at bottom level; Mice and Rabbit at middle level; Cat, Fox, Bear at top level]

    • (a) Mice and Bear
    • (b) Rabbit and Cat
    • (c) Rabbit and Fox
    • (d) Mice and Rabbit
11. 11.
    Choose the correct order of the stages of binary fission in Leishmania. [Diagrams show five stages labelled (I), (II), (III), (IV), (V)]

    • (a) I, II, III, IV, V
    • (b) I, III, II, V, IV
    • (c) I, III, V, II, IV
    • (d) I, II, III, V, IV
12. 12.
    Consider the following chemical equations I and II: I. Mg + 2HCl → MgCl₂ + H₂ II. NaOH + HCl → NaCl + H₂O The correct statement about these equations is:

    • (a) 'I' is a displacement reaction and 'II' is a decomposition reaction.
    • (b) 'I' is a displacement reaction and 'II' is double displacement reaction.
    • (c) Both 'I' and 'II' are displacement reactions.
    • (d) Both 'I' and 'II' are…
13. 13.
    In the following diagram showing dispersion of white light by a glass prism, the colours 'P' and 'Q' respectively are: [Diagram shows white light entering a prism, with P at the bottom and Q at the top of the dispersed spectrum]

    • (a) Red and Violet
    • (b) Violet and Red
    • (c) Red and Blue
    • (d) Orange and Green
14. 14.
    Consider the following three flowers namely X, Y and Z. Which flower(s) would develop into a fruit? [Diagram shows Flower X with both stamen and pistil, Flower Y with only stamen, Flower Z with only pistil]

    • (a) 'X' only
    • (b) 'Z' only
    • (c) 'X' and 'Y' only
    • (d) 'Y' and 'Z'
15. 15.
    The magnetic field inside a long straight current carrying solenoid:

    • (a) is zero.
    • (b) decreases as we move towards its end.
    • (c) increases as we move towards its end.
    • (d) is same at all points.
16. 16.
    In human eye the part which allows light to enter into the eye is:

    • (a) Retina
    • (b) Pupil
    • (c) Eye lens
    • (d) Cornea
17. 17.
    Assertion (A): It is advised that while diluting an acid one should add acid to water and not water to acid keeping the solution continuously stirred. Reason (R): The process of dissolving an acid into water is highly exothermic.

    • (a) Both (A) and (R) are true and (R) is the correct explanation of (A).
    • (b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
    • (c) (A) is true…
18. 18.
    Assertion (A): The energy which passes to the herbivores does not come back to autotrophs. Reason (R): The flow of energy in a food chain is unidirectional.

    • (a) Both (A) and (R) are true and (R) is the correct explanation of (A).
    • (b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
    • (c) (A) is true, but (R) is false.
    • (d) (A) is false, but (R) is true.
19. 19.
    Assertion (A): Amoeba takes in food using finger like extensions of the cell surface. Reason (R): In all unicellular organisms, the food is taken in by the entire cell surface.

    • (a) Both (A) and (R) are true and (R) is the correct explanation of (A).
    • (b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
    • (c) (A) is true, but (R) is false.
    • (d) (A) is false, but (R) is true.
20. 20.
    Assertion (A): Melting point and boiling point of ethanol are lower than that of sodium chloride. Reason (R): The forces of attraction between the molecules of ionic compounds are very strong.

    • (a) Both (A) and (R) are true and (R) is the correct explanation of (A).
    • (b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
    • (c) (A) is true, but (R) is false.
    • (d) (A) is false…
21. 21.
    State whether the given chemical reaction is a redox reaction or not. Justify your answer. MnO₂ + 4HCl → MnCl₂ + 2H₂O + Cl₂
22. 22.
    List two differences between the movement of leaves of a sensitive plant and the movement of a shoot towards light.
23. 23.
    Give the name of the enzyme present in the fluid in our mouth cavity. State the gland which produces it. What would happen to the digestion process if this gland stops secreting this enzyme?
24. 24.
    Let the resistance of an electrical device remain constant, while the potential difference across its two ends decreases to one fourth of its initial value. What change will occur in the current through it? State the law which helps us in solving the above stated question.
25. 25 (a).
    A light ray enters from medium A to medium B as shown in the figure. (a) Which one of the two media is denser w.r.t. the other medium? Justify your answer.
26. 25 (b).
    If the speed of light in medium A is v_a and in medium B is v_b, what is the refractive index of B with respect to A?
27. 26.
    State the rule to determine the direction of

    • (a) magnetic field produced around a straight conductor carrying current and
    • (b) force experienced by a current carrying straight conductor placed in a magnetic field which is perpendicular to it.
28. 27.
    Explain the process of transport of oxygenated and deoxygenated blood in a human body.
29. 28 (a).
    A substance 'X' is used as a building material and is insoluble in water. When it reacts with dil. HCl, it produces a gas which turns lime water milky.

    • (i) Write the chemical name and formula of 'X'.
    • (ii) Write chemical equations for the chemical reactions involved in the above statements.
30. 28 (b).
    OR: (b) A metal 'M' on reacting with dilute acid liberates a gas 'G'. The same metal also liberates gas 'G' when reacts with a base. (i) Write the name of gas 'G'. (ii) How will you test the presence of this gas? (iii) Write chemical equations for the reactions of the metal with (1) an acid and (2) a base.
31. 29 (a).
    Name the gland and the hormone secreted by it in scary situations in human beings. List any two responses shown by our body when this hormone is secreted into the blood.
32. 29 (b).
    OR: (b) In the given diagram: (i) Name the parts labelled A, B, and C. (ii) Write the functions of A and C. (iii) Reflex arcs have evolved in animals? Why? [Diagram shows a reflex arc with parts A (receptor/sensory neuron area), B (spinal cord), and C (effector/muscle)]
33. 30.
    With the help of an appropriate example, justify that some of the chemical reactions are determined by:

    • (a) Change in temperature
    • (b) Evolution of a gas
    • (c) Change in colour Give chemical equation for the reaction involved in each case.
34. 31.
    State reasons for Myopia. With the help of ray diagrams, show the:

    • (a) image formation by a myopic eye, and
    • (b) correction of myopia using an appropriate lens.
35. 32.
    What is a solenoid? When does a solenoid behave as a magnet? Draw the pattern of the magnetic field produced inside it showing the directions of the magnetic field lines.
36. 33 (a).
    Write the percentage of

    • (i) solar energy captured by the autotrophs and
    • (ii) energy transferred from autotrophs to the next level in a food chain.
37. 33 (b).
    What are trophic levels? Why do different food chains in an ecosystem not have more than four to five trophic levels? Give reason.
38. 34 (a).
    • (i) A compound 'A' with a molecular formula C₂H₄O₂ reacts with a base to give salt and water. Identify 'A', state its nature and the name of the functional group it possesses. Write chemical equation for the reaction involved.
    • (ii) When the above stated compound 'A' reacts with another compound 'B' having molecular formula C₂H₆O in the presence of an acid, a sweet smelling compound 'C' is…
39. 34 (b).
    OR: (b) (i) Name the compound formed when ethanol is heated at 443 K in the presence of conc. H₂SO₄ and draw its electron-dot structure. State the role of conc. H₂SO₄ in this reaction. (ii) What is hydrogenation? Explain it with the help of a chemical equation. State the role of this reaction in industry.
40. 35.
    Give reason for the following:

    • (a) During reproduction inheritance of different proteins will lead to altered body designs.
    • (b) Fertilization cannot take place in flowers if pollination does not occur.
    • (c) All multicellular organisms cannot give rise to new individuals through fragmentation or regeneration.
    • (d) Vegetative propagation is practised for growing only some type of plants.
    • (e) The…
41. 36 (a).
    • (i) What is meant by resistance of a conductor? Define its SI unit.
    • (ii) List two factors on which the resistance of a rectangular conductor depends.
    • (iii) How will the resistance of a wire be affected if its: (1) length is doubled, and (2) radius is also doubled? Give justification for your answer.
42. 36 (b).
    OR: (b) In an electric circuit three bulbs of 100 W each are connected in series to a source. In another circuit set of three bulbs of the same wattage are connected in parallel to the same source. (i) Will the bulbs in the two circuits glow with the same brightness? Justify your answer. (ii) Now, let one bulb in both the circuits get fused. Will the rest of the bulbs continue to glow in each…
43. 37.
    On the basis of reactivity, metals are grouped into three categories:

    • (i) Metals of low reactivity
    • (ii) Metals of medium reactivity
    • (iii) Metals of high reactivity Therefore metals are extracted in pure form from their ores on the basis of their chemical properties. Metals of high reactivity are extracted from their ores by electrolysis of the molten ore. Metals of low reactivity are extracted…
44. 38.
    All human chromosomes are not paired. Most human chromosomes have a maternal and a paternal copy, and we have 22 such pairs. But one pair called the sex chromosomes, is odd in not always being a perfect pair. Women have a perfect pair of sex chromosomes. But men have a mismatched pair in which one is normal sized while the other is a short one. (a) In humans, how many chromosomes are present in…
45. 39.
    A student took three concave mirrors of different focal lengths and performed the experiment to see the image formation by placing an object at different distances with these mirrors as shown in the following table: Case No. | Object distance | Focal length I | 45 cm | 20 cm II | 30 cm | 15 cm III | 20 cm | 30 cm Now answer the following questions: (a) List two properties of the image formed in…

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 2023 paper — FAQ