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(a) What is a reactivity… (Class 10 Science 2025, Q27)

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ScienceCBSE Class 10 · Board exam 2025, set 31/3/1 · 3 marks · Short answer

CBSE Class 10 Science 2025: question 27

Set in the CBSE Class 10 board exam of 2025, paper 31/3/1, section C, question 27, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q27 · 3 marks · Short answerMetals and Non-metals

(a) What is a reactivity series of elements? How is it developed? Arrange the following elements as they are arranged in the reactivity series: Aluminum, Calcium, Copper, Lead

(b) Write balanced chemical equation to show the reaction of iron (III) oxide () with aluminium.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 31/3/1.

Hints

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

Hint 1

Which metal can push another out of its compound?

Hint 2

Aluminium is more reactive than iron – it takes oxygen from iron oxide.

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) The reactivity series is a list of metals arranged in order of decreasing reactivity.

    ½ mark

  2. It is developed by performing displacement reactions – a more reactive metal displaces a less reactive metal from its salt solution.

    ½ mark

  3. Order: Calcium > Aluminium > Lead > Copper.

    1 mark

  4. (b) Thermit reaction:

    1 mark

Answer: (a) Metals in decreasing order of reactivity, found by displacement reactions; Ca > Al > Pb > Cu; (b)

Where the marks are

  • Definition of reactivity series (½ mark)
  • Developed through displacement reactions (½ mark)
  • Correct order Ca, Al, Pb, Cu (1 mark)
  • Balanced thermit equation (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 31/3/1: 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.