CH_3CONH_2 on reaction with NaOH and Br_2 in alcoholic medium gives : (A) CH_3COONa (B) CH_3NH_2 (C) CH_3CH_2Br (D) CH_3CH_2NH_2

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

CBSE Class 12 Chemistry 2023: question 11

Set in the CBSE Class 12 board exam of 2023, paper 56/1/1, section A, question 11, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q11 · 1 mark · MCQAmines

$C H_{3} CON H_{2}$ on reaction with NaOH and $B r_{2}$ in alcoholic medium gives :

(A) $C H_{3} COONa$
(B) $C H_{3} N H_{2}$
(C) $C H_{3} C H_{2} Br$
(D) $C H_{3} C H_{2} N H_{2}$

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

Name the reaction of an amide with Br₂/NaOH.

Hint 2

Is a carbon atom lost?

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.

This is the Hoffmann bromamide degradation, which gives an amine with one carbon fewer than the amide.
$C H_{3} C O N H_{2} + B r_{2} + 4 N a O H \to C H_{3} N H_{2} + N a_{2} C O_{3} + 2 N a B r + 2 H_{2} O$ . Option (B).
1 mark

Answer: $C H_{3} N H_{2}$ , option (B)

Where the marks are

Hoffmann bromamide product (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 paper2023 board paper, set 56/1/1: every question, by section.

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CBSE Class 12 Chemistry 2023: question 11

Hints

Step-by-step solution

Revise the chapter

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