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Which of the following is… (Class 12 Chemistry 2023, Q12)

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ChemistryCBSE Class 12 · Board exam 2023, set 56/1/1 · 1 mark · MCQ

CBSE Class 12 Chemistry 2023: question 12

Set in the CBSE Class 12 board exam of 2023, paper 56/1/1, section A, question 12, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q12 · 1 mark · MCQAmines

Which of the following is least basic ?

  1. (A)
  2. (B)
  3. (C)Aniline ()
  4. (D)

Figure in the paper: Option (C) is a benzene ring attached to NH2. See it in the official paper.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 56/1/1.

Hints

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

Hint 1

Compare the availability of the lone pair on N in each.

Hint 2

Consider the effect of attaching N to an aromatic ring.

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. In aniline the lone pair on N is delocalised into the benzene ring by resonance, so it is less available to accept a proton.

  2. Aniline is therefore less basic than and the alkylamines. Option (C).

    1 mark

Answer: Aniline, option (C)

Where the marks are

  • Resonance reduces lone-pair availability (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 paper2023 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.