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Assertion: Rusting of… (Class 10 Science SQP 2023-24, Q17)

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ScienceCBSE Class 10 · Sample paper, session 2023-24 · 1 mark · Assertion-reason

CBSE Class 10 Science sample paper 2023-24: question 17

From the official CBSE sample question paper for 2023-24, 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-basedChemical Reactions and Equations

Assertion: Rusting of Iron is endothermic in nature.
Reason: As the reaction is slow, the release of heat is barely evident.

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

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2023-24.

Hints

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

Hint 1

Does rusting release or absorb heat?

Hint 2

Why do we not notice the heat from rusting?

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: Rusting of iron is an oxidation that releases heat. It is exothermic, so the Assertion is false.

  2. Reason: Rusting is very slow, so the heat given out is barely noticeable. The Reason is true. A is false and R is true, so the answer is option (D).

    1 mark

Answer: Option (D)

Where the marks are

  • Recognises rusting is exothermic (A false) and R true (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Chemical Reactions and Equations, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2023-24: 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.