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Assertion (A) : The boiling… (Class 12 Chemistry 2025, Q15)

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ChemistryCBSE Class 12 · Board exam 2025, set 56/1/1 · 1 mark · Assertion-reason

CBSE Class 12 Chemistry 2025: question 15

Set in the CBSE Class 12 board exam of 2025, paper 56/1/1, section A, question 15, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q15 · 1 mark · Assertion-reasonCompetency-basedAlcohols, Phenols and Ethers

Assertion (A) : The boiling point of ethanol is higher than that of methoxymethane.
Reason (R) : There is intramolecular hydrogen bonding in ethanol.

  1. (A)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
  2. (B)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the 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 56/1/1.

Hints

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

Hint 1

Hydrogen bonding raises the boiling point of ethanol.

Hint 2

Is that hydrogen bonding within one molecule or between molecules?

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. Ethanol has a higher boiling point because of intermolecular hydrogen bonding, so A is true.

  2. R wrongly says the hydrogen bonding is intramolecular, so R is false. The answer is option (C).

    1 mark

Answer: Option (C)

Where the marks are

  • Recognises A is true and R is false because the H-bonding is intermolecular (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Alcohols, Phenols and Ethers, one at a time, marked against the answer key and marking points.Back to the full paper2025 board paper, set 56/1/1: 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.