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The domes of many… (Class 10 Science SQP 2025-26, Q26B)

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ScienceCBSE Class 10 · Sample paper, session 2025-26 · 3 marks · Short answer

CBSE Class 10 Science sample paper 2025-26: question 26(B)

From the official CBSE sample question paper for 2025-26, section B, question 26(B), for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q26(B) · 3 marks · Short answerCompetency-basedMetals and Non-metals

The domes of many building in Europe are made of copper. These domes now appear greenish in colour.

  1. (i)

    Why do the domes appear greenish though copper is orange-red in colour?

    1 mark
  2. (ii)

    In your opinion, should the copper domes be replaced by iron domes to overcome the problem of change of colour of copper domes?

    1 mark
  3. (iii)

    Domes used to be made from thin sheets of metals. Why did the ancient architects use copper to make domes?

    1 mark

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2025-26.

Hints

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

Hint 1

Think of the corrosion of copper in moist air.

Hint 2

Compare the rust layer on iron with the green layer on copper: which one protects the metal?

Hint 3

Which property lets a metal be beaten into thin sheets?

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. (i) Copper slowly reacts with moist carbon dioxide and oxygen in air. It forms a green layer of basic copper carbonate, , so the domes look greenish.

    1 mark

  2. (ii) No. Iron would rust in moist air, and the reddish-brown rust flakes off. This keeps exposing fresh iron, so corrosion continues and the dome weakens. The green layer on copper sticks to it and protects the metal below from further corrosion.

    1 mark

  3. (iii) Copper is highly malleable, so it can be beaten into thin sheets and shaped into curved domes. It also resists corrosion, so it lasts long.

    1 mark

Answer: (i) Green basic copper carbonate layer forms. (ii) No, iron rusts and flakes; copper's coating is protective. (iii) Copper is highly malleable (and corrosion resistant).

Where the marks are

  • Green basic copper carbonate due to corrosion (1 mark)
  • No, with reasoning about flaking rust versus protective copper layer (1 mark)
  • Malleability of copper (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Metals and Non-metals, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2025-26: 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.