Primary alkyl halide C4H9Br (a) reacted | Class 12 Chemistry Chapter Haloalkanes and Haloarenes, Haloalkanes and Haloarenes NCERT Solutions

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Academic session 2026-27, Chapter 6 in the current curriculum.

Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter Haloalkanes and Haloarenes. This page offers a step-by-step solution to the specific question from Exercise 2, Question 21:

Primary alkyl halide C4H9Br (a) reacted with alcoholic KOH to give compound (b).Compound (b) is reacted with HBr to give (c) which is an isomer of (a). When (a) is reacted with sodium metal it gives compound (d), C8H18 which is different from the compound formed when n-butyl bromide is reacted with sodium. Give the structural formula of (a) and write the equations for all the reactions.

. With detailed answers and explanations for each chapter, students can strengthen their understanding and prepare confidently for exams. Ideal for CBSE and other board students, this resource will simplify your study experience.

Question 21:

Primary alkyl halide C4H9Br (a) reacted with alcoholic KOH to give compound (b).Compound (b) is reacted with HBr to give (c) which is an isomer of (a). When (a) is reacted with sodium metal it gives compound (d), C8H18 which is different from the compound formed when n-butyl bromide is reacted with sodium. Give the structural formula of (a) and write the equations for all the reactions.

Answer:

There are two primary alkyl halides having the formula, C4H9Br. They are n - bulyl bromide and isobutyl bromide.

Therefore, compound (a) is either n-butyl bromide or isobutyl bromide.

Now, compound (a) reacts with Na metal to give compound (b) of molecular formula, C8H18, which is different from the compound formed when n-butyl bromide reacts with Na metal. Hence, compound (a) must be isobutyl bromide.

Thus, compound (d) is 2, 5-dimethylhexane.

It is given that compound (a) reacts with alcoholic KOH to give compound (b). Hence, compound (b) is 2-methylpropene.

Also, compound (b) reacts with HBr to give compound (c) which is an isomer of (a). Hence, compound (c) is 2-bromo-2-methylpropane.


Study Tips for Answering NCERT Questions:

NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:

  • Read the question carefully and focus on the core concept being asked.
  • Reference examples and data from the chapter when answering questions about Haloalkanes and Haloarenes.
  • Review previous year question papers to get an idea of how such questions may be framed in exams.
  • Practice answering questions within the time limit to improve your speed and accuracy.
  • Discuss your answers with your teachers or peers to get feedback and improve your understanding.

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Comments

  • Rahul
  • Feb 06, 2023

Koh se kon react krega


  • shilpakumari
  • Sep 19, 2019

thaanks


  • Suman Raj
  • Jun 17, 2019

Something is wrong in last reaction.


  • HPK
  • Mar 09, 2019

Superb😍


  • nidhi
  • Mar 07, 2019

thank u...


  • jyothy I
  • Mar 06, 2019

Thwnx


  • Nishant Sharma
  • Sep 15, 2018

There is a correction in there. It is written that -"compound (a) reacts with Na metal to give compound (b) of molecular formula, C8H18" but it should be "compound (a) reacts with Na metal to give compound (d) of molecular formula, C8H18"


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Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter . This page offers a step-by-step solution to the specific question from Excercise 2 , Question 21: Primary alkyl halide C4H9Br (a) reacted with alcoholic KOH to give compound (b).Compound (b) is reac....

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