Class 10 Science Pre-Board Question Paper (2025-26)

Maximum Marks: 80 | Time: 3 Hours 15 Minutes

Section A – Multiple Choice Questions

(i to xviii) Each question carries 1 mark.

(i) 2FeCl₃ + 2H₂O + (y) → 2FeCl₂ + H₂SO₄ + 2HCl. In the given chemical reaction, y is:
(a) S (b) H₂S (c) SO₂ (d) Cl₂

(ii) Why do silver objects turn black due to long exposure to air?
(a) AgN (b) Ag₂O (c) Ag₂S (d) AgNO₃

(iii) Buckminster fullerene is an allotropic form of:
(a) Phosphorus (b) Sulphur (c) Carbon (d) Tin

(iv) Which of the following statements about the given reaction are correct?
3Fe(s) + 4H₂O → Fe₃O₄(s) + 4H₂(g)
(i) Iron metal is getting oxidized
(ii) Water is getting reduced
(iii) Water is acting as a reducing agent
(iv) Water is acting as an oxidizing agent
(a) (i), (ii), (iii) (b) (iii), (iv) (c) (i), (ii), (iv) (d) (ii), (iv)

(v) 10 mL of NaOH solution is neutralized by 8 mL of HCl. How much HCl is required for 20 mL NaOH?
(a) 4 mL (b) 8 mL (c) 12 mL (d) 16 mL

(vi) Identify the type of reactions:
(i) CH₄ + 2O₂ → CO₂ + 2H₂O
(ii) Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃
(iii) CaO + H₂O → Ca(OH)₂
(iv) CuSO₄ + Zn → ZnSO₄ + Cu
(a) Combustion & Oxidation (b) Double displacement & Precipitation (c) Combination (d) Displacement

(vii) Unit of excretory system:
(a) Neuron (b) Nephron (c) Kidney (d) Lung

(viii) Reflex action is controlled by:
(a) Cerebrum (b) Spinal cord (c) Pituitary gland (d) Neuron

(ix) The brain is responsible for:
(a) Thinking (b) Regulating heartbeat (c) Balancing the body (d) All these

(x) Where does embryo develop after fertilization in flowering plant?
(a) Ovule (b) Ovary (c) Stigma (d) Pollen tube

(xi) Mendel conducted his famous experiments on:
(a) Drosophila (b) E. Coli (c) Pisum sativum (d) All of these

(xii) If 4th trophic level has 5kJ, energy at producers will be:
(a) 5 kJ (b) 50 kJ (c) 500 kJ (d) 5000 kJ

(xiii) A ray falls on mirror at 30°. Angle of reflection will be:
(a) 30° (b) 60° (c) 90° (d) 120°

(xiv) The human eye forms image at its:
(a) Cornea (b) Pupil (c) Iris (d) Retina

(xv) An electric bulb 220V, 100W. At 110V, power consumed will be:
(a) 100W (b) 75W (c) 50W (d) 25W

(xvi) Three bulbs A(40W), B(60W), C(100W) in parallel. Brightness:
(a) Same (b) A max (c) B > A (d) C < B

(xvii) Incorrect statement about magnetic field lines:
(a) Direction is given by north pole of compass
(b) Magnetic field lines are closed curves
(c) If parallel & equidistant → zero strength
(d) Relative strength shown by closeness

(xviii) Magnetic field lines of bar magnet similar to:
(a) Current-carrying wire (b) Solenoid (c) Two parallel wires (d) None

Fill in the Blanks

(i to vi) Each question carries 1 mark.

(i) The type of reaction in which a compound breaks down into two or more simpler substances is called a ______ reaction.

(ii) 2Na(s) + Cl₂(g) → ______

(iii) The ______ connects the brain to the spinal cord and helps in reflex actions.

(iv) ______ is a gas that absorbs UV radiation and protects life on Earth.

(v) The total energy consumed by an electrical appliance = product of ______ and ______.

(vi) A material through which electricity can flow easily is called a ______.

Very Short Answer Questions

Each question carries 1 mark.

1. State two characteristic features of carbon leading to large number of compounds.

2. What is corrosion?

3. Name the sodium compound used for softening hard water.

4. Why do ionic compounds have high melting points?

5. Name digestive enzymes for proteins and fats.

6. Name the two components of central nervous system.

7. Name two organisms capable of regeneration.

8. Other name for law of purity of gametes?

9. Why do lemons in glass vessel appear bigger from side?

10. When object absorbs all colours of light, what colour appears and why?

11. Frequency of AC in India?

12. Function of fuse wire?

Section B – Short Answer Type Questions

4. Why do we apply paint on iron articles? (2 Marks)

5. How is [OH⁻] affected when excess base is dissolved in NaOH? (2 Marks)

6. Write reactions of:
(i) Iron with steam
(ii) Calcium and Potassium with water

7. Name two molecules produced by digestion of starch and fat. (2 Marks)

8. Role of brain in reflex action? (2 Marks)

9. Reasons for adopting contraceptive methods? (2 Marks)

10. Difference between monohybrid & dihybrid cross. (2 Marks)

11. Distinguish between real image and virtual image. (2 Marks)

12. Why does sky appear dark instead of blue to an astronaut? (2 Marks)

13. When is force on current-carrying conductor in magnetic field largest? (2 Marks)

Section C – Application/Understanding Questions

14. (i) Metal compound A reacts with dilute HCl to produce effervescence. Gas evolved extinguishes candle. Write balanced equation if one product is CaCl₂.
(ii) What are salts? Define.
OR
(i) Name scale to measure concentration of H⁺.
(ii) Write cause of acid rain.

15. State three advantages of vegetative propagation.
OR Describe multiple fission in Plasmodium.

16. (a) Define ecosystem.
(b) Assign trophic level to frogs in food chain: grass → insects → frogs → snakes.
OR Explain trophic levels with food chain example of grass field.

17. (i) Define electrical resistivity.
(ii) In a series circuit, ammeter reads 5A. Current halves when wire length doubled. Why?
OR
(i) List factors on which resistance of a conductor depends.
(ii) Why are metals good conductors & glass bad conductor?
(iii) Why are alloys used in heating devices?

Section D – Long Answer Type Questions

18. (i) Write three properties of homologous series.
(ii) Identify alkene & alkyne from: C₂H₆, C₃H₄, C₃H₆, C₃H₈.
(iii) Draw electron dot structure of ethane.
OR
(i) Draw electron dot structure of sulphur molecule (S₈).
(ii) Why are carbon & its compounds used as fuel?

19. (i) Define excretion.
(ii) Name basic filtration unit in kidney.
(iii) Draw labelled diagram of nephron.
OR
(i) How is most of area in lungs designed for gas exchange?
(ii) Compare structure & functioning of alveoli and nephron.

20. (i) Object placed before convex lens (f = 20 cm). Find position for image at 30 cm. If object is 6 cm tall, find image height.
(ii) Image formed by convex lens same size at 50 cm. Find object distance, focal length & power.
OR
Define: (i) Optical center (ii) Focus (iii) Principal axis (iv) Aperture

This is the official Class 10th Science Pre-Board 2025-26 Question Paper with all sections included (MCQs, Fill in the blanks, Very Short, Short, Long Answer Questions).