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(a) Give the chemical name… (Class 10 Science 2026, Q27A)

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ScienceCBSE Class 10 · Board exam 2026, set 31/5/1 · 3 marks · Short answer

CBSE Class 10 Science 2026: question 27(A)

Set in the CBSE Class 10 board exam of 2026, paper 31/5/1, section B, question 27(A), for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q27(A) · 3 marks · Short answerAcids, Bases and Salts

(a) Give the chemical name and formula of Plaster of Paris.
(b) Write the chemical equation of its preparation.
(c) Give any two uses of it.

  1. (a)

    Give the chemical name and formula of Plaster of Paris.

    0 marks
  2. (b)

    Write the chemical equation of its preparation.

    0 marks
  3. (c)

    Give any two uses of it.

    0 marks

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 31/5/1.

Hints

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

Hint 1

Plaster of Paris is made from gypsum.

Hint 2

'Hemi' means half — how many water molecules per formula unit remain?

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) Chemical name: calcium sulphate hemihydrate; formula .

    1 mark

  2. (b) Gypsum is heated at 373 K:

    1 mark

  3. (c) Uses: (1) supporting fractured bones in the right position by doctors; (2) making toys, decorative materials and smooth surfaces.

    1 mark

Answer: (a) Calcium sulphate hemihydrate, CaSO₄·½H₂O; (b) CaSO₄·2H₂O → (373 K) CaSO₄·½H₂O + 3/2 H₂O; (c) plastering fractured bones, making toys.

Where the marks are

  • Chemical name (½ mark)
  • Formula (½ mark)
  • Preparation equation with 373 K (1 mark)
  • Two uses (½ + ½ marks)

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 paper2026 board paper, set 31/5/1: 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.