AJNISH GUPTA & BHARTI GUPTA

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2 Performance Booster Organic Chemistry For Board Examinations By AJNISH GUPTA & BHARTI GUPTA Professor of Organic Chemistry

3 Copyright 2015 by Ajnish Gupta All rights reserved. No part of this publication may be reproduced, stored in a database or retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written Permission of the writter. First Indian Print: September 2015 This edition is manufactured in Indian and is authorized for sale only in India, Bangladesh, Pakistan, Nepal, Sri Lanka & Maldeves. Printed & Distributed by: Udaan Classes Pvt. Ltd. Rainbow building, Patna & Madhur Satyapushpa Shubhash Nagar, Kota Price: Rs. 300/-

4 Preface The guiding principle in writing this book was to create a textbook for students- a textbook that presents the material in a way that they learn to solve all the questions of previous year board questions by themself at appropriate space. This spacing area help the students to think for the length of the answer which they have to write. As the school examination plays the most important role in the life of Student and their marks are counted in many espect of life and from todays scenario, the importance of school exa mina tion is ma ximise by government a s fixed w eighta ge of these examinations are counted in the process of admission to any engineering or higher level educational programme. Now one question arises, what should be the way to study to get maximum percentage. The answer is so simple and we know it well. We should plan our way of studies in such a way that along with the school studies we should also keep an eye on what types of questions are being asked in the real examination. We had prepared this workbook in chapterwise manner which are further divided into topics, in the same way in which we taught in our classroom so that you should feel easy to understand & practice correctly. For better picture of the topic, the questions in each topic have been arranged as per their marks and in ascending order i.e i.e. 1 marks questions, 2 Marks questions, 3 Marks questions & 5 Marks questions. We had tried our best to answer all the questions according to CBSE marking scheme so that student can learn correct way to get more marks in exam. So this book will surely help you to get a high success in 12th class board examination. However we had put our best efforts in preparing this book, but if any error or what so ever has been skipped out, we will by heart welcome your suggestion. We would like to thank the editors and production staff for their efforts in bringing out the book. Suggestions from readers for the improvement of the book are welcome. Ajnish Kumar Gupta & Bharti Gupta Ajnish@OrganicChemistry

5 Acknowledgement We are thankful to all the teachers who taught us during the concept building session of our life specially Dr. Nizamuddin sir, senior Chandra Vijay Rao and Dr. Vijay Pratima Mittal madam. We have written this book to remove the fever of organic chemistry from mind of students. We particularly want to thank many wonderful and talented students whom we have taught over the years who in turn taught us how to be a good teacher and how we can help others. We want to make this book as user friendly as possible, and we will appreciate any comments that will help us to achieve this goal in future editions. Finally, this edition has been presented before you with efforts to make it error free. Any that remain are our responsibility; if you find any, please let us know so they can be corrected in future printing. Ajnish Gupta & Bharti Gupta Professors of Organic Chemistry Ajnish@OrganicChemistry

6 Table of Contents Chapter Title Page 1. Haloalkanes and Haloarenes : 1 Mark Questions Marks Questions Marks Question Alcohols, Phenols and Ethers : 1 Mark Questions & 23 2 Marks Questions & 23 3 Marks Question & Aldehydes, Ketones and Carboxylic Acids : 1 Mark Questions & Marks Questions & Marks Question & Marks Questions & Organic Compounds containing Nitrogen : 1 Mark Questions Marks Questions Marks Question Biomolecules : 1 Mark Questions & Marks Questions & Marks Question & Polymers : 1 Mark Questions Marks Questions Marks Question Chemistry in Everyday Life : 1 Mark Questions Marks Questions Marks Question Answers :

7 Dedication Dedicated to all those students who are in fever of Organic Chemistry.

8 Marking Scheme in Board Examinations Theory : Chapters Marks Organic Inorganic Physical Unit I Unit II Unit III Unit IV Unit V Unit VI Unit VII Unit VIII Unit IX Unit X Unit XI Unit XII Unit XIII Unit XIV Unit XV Unit XVI Solid State Solutions Electrochemistry Chemical Kinetics Surface Chemistry General Principles and Processes of Isolation of Elements p -Block Elements d -and f -Block Elements Coordination Compounds Haloalkanes and Haloarenes Alcohols, Phenols and Ethers Aldehydes, Ketones and Carboxylic Acids Organic Compounds containing Nitrogen Biomolecules Polymers Chemistry in Everyday Life Total Marks : 70 Practical : Evaluation Scheme Marks Volumetric Analysis Salt Analysis Content Based Experiment Project Work Class Record and Viva Total Marks : 30

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10 Haloalkanes and Haloarenes Chapter 01 Haloalkanes and Haloarenes 1 Mark Questions: 1. Write the IUPAC name of the following compound: (CH 3 ) 3CCH 2Br. [Delhi 2011] 2. Write the IUPAC name of the following compound: CH 2=CHCH 2Br. [All India 2011] 3. Draw the structure of 1,4-Dibromobut-2-ene. [Delhi 2011] 4. Draw the structure of 2-(2-Bromophenyl)butane. [Delhi 2011] 5. Draw the structure of 2-(2-Chlorophenyl)-1-iodooctane. [All India 2011] 6. Draw the structure of the following compound: 1-bromo-4-sec-butyl-2-methylbenzene. [All India 2011] 1

11 Haloalkanes and Haloarenes 7. Draw the structure of the following organic compound: 2-Chloro-3-methylpentane [All India 2011] 8. Which will react faster in S N 2 displacement: 1-Bromopentane or 2-Bromopentane and why? [Foreign 2011] 9. Draw the structure of the following compound: 1-(4-Chlorophenyl)-2-methylpropane [Delhi 2011] CH 2=C CH2Br 10. Give the IUPAC name of the following compound: [Delhi 2012] CH What happens when bromine attacks over CH 2=CH CH 2 C CH? [All India 2012] 12. Write the IUPAC name of (CH 3) 2CH.CH(Cl)CH 3 [Delhi 2013] 13. Write the IUPAC name of CH 3 CH CH 2 CH=CH 2 Cl [Delhi 2013] 14. What happens when CH 3 Br is treated with KCN? [Delhi 2013] 2

12 Haloalkanes and Haloarenes 15. What happens when Ethyl chloride is treated with aqueous KOH? [Delhi 2013] CH Write the IUPAC name of CH 3CH=CH C CH 3 Br [Delhi 2013] 17. Which compound in the following pair undergoes faster towards S N 1 reaction? (i) Cl (ii) Cl [Delhi 2013] CH 3 C CH CH Write the IUPAC name of the following compound: CH 3 Cl CH 3 [All India 2013] 19. Write the IUPAC name of the following compound: CH [All India 2013] 3 Cl 20. Write the IUPAC name of the following compound: Cl CH 3 CH CH 2 CH CH 3 Br Cl [All India 2013] 21. How Methylbromide be preferentially converted to methyl isocyanide? [Delhi 2013] 3

13 Haloalkanes and Haloarenes 22. Identify the chiral molecule in the following pair: Cl Cl [Delhi 2014] 23. Draw the structure of 2-Bromopentane: [Delhi 2014] 24. Which would undergo S N 2 reaction faster in the following pair and why? CH 3 CH 3 CH 2 Br and CH 3 C CH3 Br [Delhi 2015] 25. Which would undergo S N 1 reaction faster in the following pair? CH 3 CH 2 CH 2 Br and CH 3 CH CH 3 Br [All India 2015] 2 Marks Questions: 26. Explain why (i) alkyl halides, though polar, are immiscible with water? (ii) Grignard s reagent should be prepared under anhydrous conditions? [Foreign 2012] 4

14 27. Account for the following: (i) Haloalkanes and Haloarenes The C Cl bond length in chlorobenzene is shorter than that in CH 3 Cl. (ii) Chloroform is stored in closed dark brown bottles. [Delhi 2013] 28. Chlorobenzene is extremely less reactive towards a nucleophilic substitution reaction. Give two reasons for the same. [Delhi 2013] 29. Write the mechanism of the following reaction: HBr CH CH OH CH CH Br + H O [Delhi 2014] 5

15 Haloalkanes and Haloarenes 30. (i) Which alkyl halide from the following pair is chiral and undergoes faster S N 2 reactions? (ii) (a) Br (b) Out of S N 1 and S N 2, which reaction occurs with (a) inversion of configuration? (b) racemisation? [All India 2014] 31. Draw the structure of major monohalo product in each of the following reactions: SOCl2 (i) OH (ii) CH 2 CH=CH 2 + HBr Peroxide Br [All India 2014] 32. Write chemical equations when (i) Ethylchloride is treated with aqueous KOH. (ii) Chlorobenzene is treated with CH 3 COCl in the presence of anhydrous AlCl 3.[Foreign 2014] 6

16 Haloalkanes and Haloarenes 33. (i) Which alkyl halide from the following pairs would you expect to react more rapidly by an S N 2 mechanism and why? CH 3 CH 2 CH CH 3 Br CH 3 CH 2 CH 2 CH 2 Br (ii) Racemisation occurs in S N 1 reactions. Why? [Foreign 2014] 34. Write the structures of the following organic halogen compounds: (i) p-bromochlorobenzene (ii) 1-Chloro-4-ethylcyclohexane [All India 2014] 35. What are ambident nucleophiles? Explain with an example. [All India 2014] 7

17 Haloalkanes and Haloarenes 36. Draw the structures of the following organic halogen compounds: (i) 4-Tert-butyl-3-iodoheptane (ii) 4-Bromo-3-methylpent-2-ene [All India Write the IUPAC names of the following compounds: (i) CH 2 = CHCH 2 Br (ii) (CCl 3 ) 3 CCl [All India 2014] 3 Marks Questions: 38. Answer the following: (i) (ii) Haloalkanes easily dissolve in organic solvents than haloarene. Why? What is known as racemic mixture? Give an example. (iii) Of the two bromo derivatives, C 6 H 5 CH(CH 3 )Br and (C 6 H 5 )CH(C 6 H 5 )Br, which one is more reactive in S N 1 substitution reaction and why? [Delhi 2011] 8

18 Haloalkanes and Haloarenes 39. Rearrange the compounds of each of the following sets in order of reactivity towards S N 2 displacement. (i) (ii) 2-Bromo-2-methylbutane, 1-Bromopentane, 2-Bromopentane. 1-Bromo-3-methylbutane, 2-Bromo-2-methylbutane, 3-Bromo-2-methylbutane. (iii) 1-Bromobutane, 1-Bromo-2, 2-Dimethylpropane, 1-Bromo-2-methylbutane, 1-Bromo-3-methylbutane. [All India 2011] 40. (i) Write a chemical test to distinguish between: (a) Chlorobenzene and Benzyl chloride. (b) Chloroform and Carbontetrachloride. (ii) Why is Methylchloride hydrolysed more easily than Chlorobenzene? [All India 2011] 41. Complete the following reactions: H H H + HBr [Foreign 2011] 9

19 Haloalkanes and Haloarenes 42. Although chlorine is an electron w ithdraw ing group, yet it is ortho, para-directing in electrophilic aromatic substitution reactions. Explain, why is it so? [Delhi 2012] 43. Answer the following questions: (i) (ii) What is meant by chirality of a compound? Give an example. Which one of the following compounds is more easily hydrolysed by KOH and why? CH 3CHClCH 2CH 3 or CH3CH 2CH2CH2Cl [All India 2012] 10

20 44. Give reasons for the following: (i) Haloalkanes and Haloarenes Ethyl iodide undergoes S N 2 reaction faster than ethyl bromide. (ii) ( ) 2-butanol is optically inactive. (iii) C X bond length in halobenzene is smaller than C X bond length in CH 3 X.[All India 2013] 45. Explain the following: The dipole moment of Chlorobenzene is lower than that of Cyclohexylchloride. [Delhi 2013] 11

21 Haloalkanes and Haloarenes 46. (i) Draw the structures of major monohalo products in each of the following reactions: (a) CH 2OH PCl 5 (b) CH 2 CH=CH 2 + HBr (ii) Which halogen compound in each of the following pairs will react faster in S N 2 reaction? (a) CH3Br or CH3I (b) (CH 3) 3C Cl or CH 3 Cl [Delhi 2014] 47. Write the product of the following reactions: (a) CH 3 Cl + KCN? (b) Cl + CH Cl 3 Anhyd. AlCl 3? +? [Delhi 2014] 12

22 48. Give reasons: (i) (ii) Haloalkanes and Haloarenes n-butyl bromide has higher boiling point than t-butyl bromide. Racemic mixture is optically inactive. (iii) The presence of nitro group ( NO 2 ) at o/p positions increases the reactivity of haloarenes towards nucleophilic substitution reactions. [Delhi 2015] 13

23 Haloalkanes and Haloarenes 49. How can the following conversions be carried out? (i) Aniline to Bromobenzene (ii) Chlorobenzene to 2-Chloroacetophenone (iii) Chloroethane to Butane Or What happens when (i) Chlorobenzene is treated with Cl 2 /FeCl 3? (ii) Ethyl chloride is treated with AgNO 2? (iii) 2-Bromopentane is treated with alcoholic KOH? Write the chemical equations in support of your answer. [All India 2015] 14

HALOALKANES AND HALOARENES

Unit - 10 HALOALKANES AND HALOARENES 1. Write the IUPAC names of the following compounds. Br CH = CH C CH (vi) (vii) (ix) (CCl 3 ) 3 CCl 103 XII Chemistry 2. Write the structure of following halogen compounds