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Assertion (A): Care… (Class 12 Chemistry SQP 2025-26, Q14)

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ChemistryCBSE Class 12 · Sample paper, session 2025-26 · 1 mark · Assertion-reason

CBSE Class 12 Chemistry sample paper 2025-26: question 14

From the official CBSE sample question paper for 2025-26, section A, question 14, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q14 · 1 mark · Assertion-reasonCompetency-basedSolutions

Assertion (A): Care should always be taken to ensure that solutions that flow in the blood stream are of the same osmotic pressure as that of the blood.
Reason (R): Sodium ion and potassium ions are responsible for maintaining proper osmotic pressure balance inside and outside of the cells of organism.

Select the most appropriate answer from the options given below:

  1. (A)Both A and R are true, and R is the correct explanation of A.
  2. (B)Both A and R are true, and R is not the correct explanation of A.
  3. (C)A is true but R is false.
  4. (D)A is false but R is true

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2025-26.

Hints

Open one hint at a time and try again before the next.

Hint 1

Consider what happens to blood cells in hypotonic or hypertonic solutions.

Hint 2

Does the role of Na⁺/K⁺ explain the need for isotonic IV fluids?

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. A is true: solutions in the blood must be isotonic, otherwise endosmosis or exosmosis damages the cells.

  2. R is also true (Na⁺/K⁺ maintain osmotic balance), but it does not explain why intravenous solutions must be isotonic.

    1 mark

Answer: Option (B)

Where the marks are

  • Both true, R not the explanation (1 mark)

Revise the chapter

  • Chapter: Solutions (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Solutions, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2025-26: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.