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Assertion (A) : Aniline is… (Class 12 Chemistry 2024, Q16)

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ChemistryCBSE Class 12 · Board exam 2024, set 56/1/1 · 1 mark · Assertion-reason

CBSE Class 12 Chemistry 2024: question 16

Set in the CBSE Class 12 board exam of 2024, paper 56/1/1, section A, question 16, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q16 · 1 mark · Assertion-reasonCompetency-basedAmines

Assertion (A) : Aniline is a stronger base than ammonia.
Reason (R) : The unshared electron pair on nitrogen atom in aniline becomes less available for protonation due to resonance.

  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 2024 board paper, set 56/1/1.

Hints

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

Hint 1

Compare how available the N lone pair is in aniline and in ammonia.

Hint 2

Resonance with the ring lowers basicity.

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. The lone pair on N in aniline is delocalised into the ring by resonance, so it is less available for protonation.

  2. Aniline is therefore a weaker base than ammonia. (A) is false and (R) is true.

    1 mark

Answer: Option (D)

Where the marks are

  • A false, R true (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Amines, one at a time, marked against the answer key and marking points.Back to the full paper2024 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.