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(I) Convert the… (Class 12 Chemistry SQP 2026-27, Q26)

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ChemistryCBSE Class 12 · Sample paper, session 2026-27 · 3 marks · Short answer

CBSE Class 12 Chemistry sample paper 2026-27: question 26

From the official CBSE sample question paper for 2026-27, section C, question 26, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q26 · 3 marks · Short answerAmines

(I) Convert the following;
a) Nitrobenzene to flourobenzene
b) Benzoic acid to benzylamine (2)

(II) Aniline undergoes electrophilic substitution reactions readily. However, acetylation of aniline is required to obtain monosubstituted products. Give reason for your answer (1)

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2026-27.

Hints

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

Hint 1

(a) Fluorine is introduced through a diazonium salt with fluoroboric acid.

Hint 2

(b) Turn –COOH into –CONH₂, then reduce the amide.

Hint 3

(II) How does attaching an acetyl group affect the availability of the N lone pair?

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)(a)

    1 mark

  2. (I)(b)

    1 mark

  3. (II) The group strongly activates the ring by donating its lone pair, so substitution occurs at all o/p positions (e.g. 2,4,6-tribromoaniline forms).

    ½ mark

  4. Acetylation converts to . The N lone pair is now also delocalised onto the C=O group, so its activating effect drops. Substitution is controlled and gives mainly the para monosubstituted product, and the amide is hydrolysed back afterwards.

    ½ mark

Answer: (a) Reduction → diazotisation → /heat (Balz–Schiemann); (b) amide formation → reduction; (II) acetylation lowers the activating effect of –NH₂, giving monosubstitution.

Where the marks are

  • Correct sequence for nitrobenzene → fluorobenzene (1 mark)
  • Correct sequence for benzoic acid → benzylamine (1 mark)
  • –NH₂ strongly activating, giving polysubstitution (½ mark)
  • Acetamido group less activating due to resonance with C=O (½ mark)

Revise the chapter

  • Chapter: Amines (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Amines, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2026-27: 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.