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Give reasons : (Class 10 Science 2026, Q26b)

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ScienceCBSE Class 10 · Board exam 2026, set 31/2/1 · 3 marks · Short answer

CBSE Class 10 Science 2026: question 26(b)

Set in the CBSE Class 10 board exam of 2026, paper 31/2/1, 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 answerMetals and Non-metals

Give reasons :

  1. (i)

    Metal sulphides and carbonates should be converted to their metal oxides in the process of extraction of metals.

    1 mark
  2. (ii)

    Aluminium oxide is considered as an amphoteric oxide.

    1 mark
  3. (iii)

    Metals like Na, K, Ca and Mg are never found in their free state in nature.

    1 mark

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 31/2/1.

Hints

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

Hint 1

What do roasting and calcination produce, and why is that product preferred?

Hint 2

An amphoteric oxide behaves as both acidic and basic.

Hint 3

Where are these metals in the reactivity series?

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) It is easier to obtain a metal from its oxide than from its sulphide or carbonate, because the oxide can be readily reduced (e.g. by carbon). So sulphide ores are roasted and carbonate ores are calcined to convert them to oxides first.

    1 mark

  2. (ii) Aluminium oxide reacts with both acids and bases to form salt and water, so it is amphoteric:

    1 mark

  3. (iii) Na, K, Ca and Mg are highly reactive metals at the top of the reactivity series. They readily combine with oxygen, water and other substances, so they are always found in the combined state, never free.

    1 mark

Answer: (i) Oxides are easier to reduce to metal; (ii) Al₂O₃ reacts with both acids and bases giving salt and water; (iii) They are highly reactive, so exist only in combined state.

Where the marks are

  • Metal oxides are easier to reduce to metals (1 mark)
  • Al₂O₃ reacts with both acids and bases forming salt and water (1 mark)
  • These metals are highly reactive, so found combined (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 paper2026 board paper, set 31/2/1: 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.