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For Questions number 17 to 20… (Science 2025 31/2/1 Q17)

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ScienceCBSE Class 10 · Board exam 2025, set 31/2/1 · 1 mark · Assertion-reason

CBSE Class 10 Science 2025: question 17

Set in the CBSE Class 10 board exam of 2025, paper 31/2/1, section A, question 17, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q17 · 1 mark · Assertion-reasonCompetency-basedMetals and Non-metals

For Questions number 17 to 20, two statements are given — one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to these questions from the codes (A), (B), (C) and (D) as given below.

Assertion (A): The metals high up in the reactivity series cannot be obtained from their compounds by heating with carbon.

Reason (R): Displacement reactions can also be used to obtain metal.

  1. (A)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
  2. (B)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
  3. (C)Assertion (A) is true, but Reason (R) is false.
  4. (D)Assertion (A) is false, but Reason (R) is true.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 31/2/1.

Hints

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

Hint 1

How are Na and Al actually extracted?

Hint 2

Does displacement explain why carbon cannot reduce these oxides?

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. Assertion: metals high in the reactivity series (such as Na, Mg, Al) have a greater affinity for oxygen than carbon has. So carbon cannot reduce their oxides, and they are obtained by electrolysis. A is true.

  2. Reason: a more reactive metal can displace a less reactive metal from its compound. For example, the thermit reaction gives Fe from . R is true.

  3. However, displacement does not explain why carbon fails for very reactive metals. R is not the explanation of A, so the answer is (B).

    1 mark

Answer: (B)

Where the marks are

  • Recognises both statements as true but unrelated, option (B) (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 paper2025 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.