CBSE 10th Science Exam 2025-26: Important Assertion/Reason Questions with Answer

This article is extremely important for students preparing for the CBSE Class 10 Science examination in 2025-26. Assertion and Reason questions are crucial for scoring well in the board exams.

These questions test your conceptual understanding and strengthen your logical thinking. In this article, we have compiled important Assertion-Reason questions from all chapters of Physics, Chemistry, and Biology.

You can download PDFs for free from the table below and further enhance your exam preparation.

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CBSE Class 10 Science Assertion Reason Questions 2025-26

Q. No.1: Assertion (A): A rainbow is always formed in a direction opposite to that of the Sun.

Reason (R): White light is composed of seven colors.

A. Both A and R are true, and R is correct explanation of the assertion.

B. Both A and R are true, but R is not the correct explanation of the assertion.

C. A is true, but R is false.

D. A is false, but R is true.

Answer: B. Both A and R are true, but R is not the correct explanation of the assertion.

Q. No.2: Assertion (A): Addition of water to a drum containing calcium oxide makes the drum hot if touched from outside.

Reason (R): Reaction between calcium oxide and water is an endothermic reaction.

A. Both A and R are true, and R is the correct explanation of the assertion.

B. Both A and R are true, and R is not the correct explanation of the assertion.

C. A is true, but R is false.

D. A is false, but R is true.

Answer: C. A is true, but R is false.

Q. No.3: Assertion (A): An incident light ray is passing through the centre of curvature of a concave mirror. After reflection, it retraces its path.

Reason (R): Angle of incidence = Angle of reflection = 0∘

A. Both A and R are true, and R is the correct explanation of the assertion.

B. Both A and R are true, but R is not the correct explanation of the assertion.

C. A is true, but R is false.

D. A is false, but R is true.

Answer: A. Both A and R are true, and R is the correct explanation of the assertion.

Q. No. 4: Assertion (A): Metallic oxides react with acids to form salt and water.

Reason (R): Metallic oxides are basic oxides.

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.

Answer: A. Both A and R are true, and R is the correct explanation of the assertion.

Q. No. 5: Assertion (A): The melting point of NaCl is high.

Reason (R): Ionic compounds have a strong electrostatic force of attraction.

A. Both A and R are true, and R is the correct explanation of the assertion.

B. Both A and R are true, and R is not the correct explanation of the assertion.

C. A is true, but R is false.

D. A is false, but R is true.

Answer: A. Both A and R are true, and R is the correct explanation of the assertion.

Q. No. 6: Assertion (A): Translocation of food takes place across the phloem.

Reason (R): Phloem is a vascular tissue that has a flow of materials in upward direction only.

A. Both A and R are true, and R is the correct explanation of the assertion.

B. Both A and R are true, and R is not the correct explanation of the assertion.

C. A is true, but R is false.

D. A is false, but R is true.

Answer: C. A is true, but R is false.

Q. No. 7: Assertion (A): All arteries carry oxygenated blood from the heart to various organs of the body.

Reason (R): Pulmonary vein carries oxygenated blood to the heart.

A. Both A and R are true, and R is the correct explanation of the assertion.

B. Both A and R are true, and R is not the correct explanation of the assertion.

C. A is true, but R is false.

D. A is false, but R is true.

Answer: D. A is false, but R is true.

Q. No. 8: Assertion (A): There is no digestion of proteins in the mouth.

Reason (R): Saliva contains salivary amylase.

A. Both A and R are true, and R is the correct explanation of the assertion.

B. Both A and R are true, and R is not the correct explanation of the assertion.

C. A is true, but R is false.

D. A is false, but R is true.

Answer: B. Both A and R are true, and R is not the correct explanation of the assertion.

Q. No. 9: Assertion (A): Kidney produces the urine by the process of ultrafiltration.

Reason (R): Urine is stored in the urinary bladder.

A. Both A and R are true, and R is the correct explanation of the assertion.

B. Both A and R are true, and R is not the correct explanation of the assertion.

C. A is true, but R is false.

D. A is false, but R is true.

Answer: B. Both A and R are true, and R is not the correct explanation of the assertion.

Q. No. 10: Assertion (A): Water in the deep sea appears blue.

Reason (R): The scattering of the blue component of the white sunlight by tiny molecules is responsible for blue appearance of ocean.

A. Both A and R are true, and R is correct explanation of the assertion.

B. Both A and R are true, but R is not the correct explanation of the assertion.

C. A is true, but R is false.

D. A is false, but R is true.

Answer: A. Both A and R are true, and R is correct explanation of the assertion.

CBSE Class 10 Science Assertion and Reason Question PDF

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