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An element 'X' is… (Class 10 Science SQP 2025-26, Q26A)

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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(A)

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

Q26(A) · 3 marks · Short answerMetals and Non-metals

An element 'X' is stored in kerosene, and cannot be extracted from its ore using a reducing agent. 'X' forms an ionic compound on reaction with chlorine.

  1. (i)

    Can we store 'X' in water? Give reason to support your answer.

    1 mark
  2. (ii)

    Identify element 'X'. Name the process used and write the equation for extraction of 'X' from its ore.

    2 marks

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

Which metals are kept under kerosene, and why?

Hint 2

Metals high in the activity series cannot be reduced by carbon. How are they obtained from their molten chlorides?

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) No. X is stored in kerosene because it is very reactive. It reacts vigorously and exothermically with water, and the hydrogen produced catches fire.

    1 mark

  2. (ii) X is a highly reactive metal at the top of the activity series that forms an ionic chloride: X = sodium (Na). Potassium is also acceptable.

    ½ mark

  3. Such metals cannot be reduced by carbon, so they are extracted by electrolytic reduction (electrolysis of molten NaCl).

    ½ mark

  4. At cathode:
    At anode:

    1 mark

Answer: (i) No, it reacts violently with water and catches fire. (ii) Sodium; electrolytic reduction of molten NaCl; cathode , anode

Where the marks are

  • No, with reason: violent reaction with water / catches fire (1 mark)
  • Identifies sodium (or potassium) (½ mark)
  • Names electrolytic reduction (½ mark)
  • Correct electrode equations (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.