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A compound 'X' with… (Class 12 Chemistry 2024, Q28)

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ChemistryCBSE Class 12 · Board exam 2024, set 56/5/1 · 3 marks · Short answer

CBSE Class 12 Chemistry 2024: question 28

Set in the CBSE Class 12 board exam of 2024, paper 56/5/1, section C, question 28, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q28 · 3 marks · Short answerAmines

A compound 'X' with molecular formula reacts with to give a solid, insoluble in alkali. Identify 'X' and give the IUPAC name of the product. Write the reaction involved.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 56/5/1.

Hints

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

Hint 1

Hinsberg's test: a sulphonamide insoluble in KOH has no H on nitrogen.

Hint 2

Draw all isomers of and pick the secondary amine.

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. A product with Hinsberg's reagent () that is insoluble in alkali shows that X is a secondary amine; the sulphonamide has no acidic N–H. The only 2° amine with formula is , N-methylethanamine, so X = N-methylethanamine.

    1 mark

  2. Reaction:

    1 mark

  3. IUPAC name of the product: N-ethyl-N-methylbenzenesulphonamide

    1 mark

Answer: X = N-methylethanamine (); product: N-ethyl-N-methylbenzenesulphonamide

Where the marks are

  • Identifies X as the secondary amine N-methylethanamine (1 mark)
  • Correct reaction with Hinsberg reagent (1 mark)
  • IUPAC name N-ethyl-N-methylbenzenesulphonamide (1 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 paper2024 board paper, set 56/5/1: 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.