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Answer the following. (Class 12 Chemistry 2026, Q21)

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ChemistryCBSE Class 12 · Board exam 2026, set 56/5/1 · 2 marks · Very short answer

CBSE Class 12 Chemistry 2026: question 21

Set in the CBSE Class 12 board exam of 2026, paper 56/5/1, section B, question 21, for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q21 · 2 marks · Very short answerBiomolecules

Answer the following.

  1. (a)

    Write any two fat soluble vitamins.

    1 mark
  2. (b)

    How will you confirm the presence of five – OH groups in a glucose molecule, which are attached to different carbon atoms ?

    1 mark

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 56/5/1.

Hints

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

Hint 1

Fat-soluble vitamins are stored in liver and adipose tissue; recall the four letters.

Hint 2

Which reagent converts every –OH into an acetate ester?

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) Any two of the fat-soluble vitamins: Vitamin A and Vitamin D (vitamins E and K are also fat soluble).

    1 mark

  2. (b) On acetylation with acetic anhydride, glucose forms a stable glucose pentaacetate. This shows that it contains five –OH groups.

    Since the pentaacetate is stable, the five –OH groups must be on different carbon atoms; two –OH groups on the same carbon would be unstable.

    1 mark

Answer: (a) Vitamins A and D (or E, K); (b) acetylation with acetic anhydride gives stable glucose pentaacetate

Where the marks are

  • Any two of A, D, E, K (½ + ½ marks)
  • Acetylation with acetic anhydride gives stable glucose pentaacetate (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 paper2026 board paper, set 56/5/1: 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.