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Which of the following… (Class 10 Science SQP 2026-27, Q20)

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ScienceCBSE Class 10 · Sample paper, session 2026-27 · 1 mark · MCQ

CBSE Class 10 Science sample paper 2026-27: question 20

From the official CBSE sample question paper for 2026-27, section B, question 20, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q20 · 1 mark · MCQAcids, Bases and Salts

Which of the following salts contain water of crystallisation: (i) Plaster of Paris, (ii) Washing soda, (iii) Baking soda and (iv) Gypsum.

  1. (A)(i), (ii) and (iii)
  2. (B)(i), (iii) and (iv)
  3. (C)(ii), (iii) and (iv)
  4. (D)(i), (ii) and (iv)

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2026-27.

Hints

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

Hint 1

Write the chemical formula of each salt.

Hint 2

Look for '·xH₂O' in each formula. Which salt has none?

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. Formulae: Plaster of Paris , washing soda , gypsum . All three contain water of crystallisation.

    ½ mark

  2. Baking soda is and has no water of crystallisation. So the answer is (i), (ii) and (iv), option (D).

    ½ mark

Answer: (i), (ii) and (iv), option (D)

Where the marks are

  • Identifies Plaster of Paris, washing soda and gypsum as hydrated salts and baking soda as anhydrous; chooses (D) (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Acids, Bases and Salts, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2026-27: 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.