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Assertion (A)… (Class 12 Chemistry SQP 2024-25, Q15)

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ChemistryCBSE Class 12 · Sample paper, session 2024-25 · 1 mark · Assertion-reason

CBSE Class 12 Chemistry sample paper 2024-25: question 15

From the official CBSE sample question paper for 2024-25, section A, question 15, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q15 · 1 mark · Assertion-reasonCompetency-basedBiomolecules

Assertion (A) Glucose does not form the hydrogensulphite addition product with .
Reason (R): Glucose exists in a six-membered cyclic structure called pyranose structure.

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 but 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 2024-25.

Hints

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

Hint 1

Think about why glucose fails some aldehyde tests.

Hint 2

Is the cyclic structure itself the direct explanation the examiner wants?

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. Glucose has no free –CHO group, so it does not give a bisulphite addition product. A is true.

  2. Glucose does exist as a six-membered pyranose ring, so R is true. As per the scheme, R is not taken as the correct explanation. Option (B).

    1 mark

Answer: Option (B)

Where the marks are

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

Revise the chapter

Practise this chapterBoard-style questions from Biomolecules, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2024-25: 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.