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2 g of green coloured… (Class 10 Science 2026, Q26)

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

CBSE Class 10 Science 2026: question 26

Set in the CBSE Class 10 board exam of 2026, paper 31/3/1, section B, question 26, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q26 · 3 marks · Short answerChemical Reactions and Equations

2 g of green coloured crystals of ferrous sulphate are heated in a dry boiling tube. Name the type of chemical reaction taking place. Write the balanced chemical equation for the reaction. Is this an exothermic or an endothermic reaction ?

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 31/3/1.

Hints

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

Hint 1

One compound breaks into several products when heated. What kind of reaction is that?

Hint 2

The products are ferric oxide and two oxides of sulphur. Does the reaction need heat or give out heat?

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. Type of reaction: thermal decomposition reaction. On heating, the green crystals first lose water and turn white, then break down into a brown solid and gases with the smell of burning sulphur.

    1 mark

  2. Balanced equation:

    1 mark

  3. It is an endothermic reaction, because heat must be absorbed continuously for the decomposition to take place.

    1 mark

Answer: Thermal decomposition; 2FeSO₄(s) → Fe₂O₃(s) + SO₂(g) + SO₃(g) on heating; endothermic.

Where the marks are

  • Names thermal decomposition (1 mark)
  • Correct balanced equation (1 mark; ½ deducted if unbalanced)
  • States endothermic (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Chemical Reactions and Equations, one at a time, marked against the answer key and marking points.Back to the full paper2026 board paper, set 31/3/1: 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.