Mechanism of Organic Reactions For world of competitions By AJNISH GUPTA & BHARTI GUPTA Professor of Organic Chemistry (i) 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 Reprint, 2015 This edition is ma nufa ctured in India n a nd 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 9122057123 Price: Rs. 499/- (ii) AIPMT & other medical exams from 2000 to 2015. Ajnish Kumar Gupta & Bharti Gupta Ajnish@OrganicChemistry. In this book balance has to be achieved between the number of questions and the quality of the questions.a textbook that presents the ma terial in a way tha t they le arn to solve all the questions along with the strategy to approach the problems. This book covers mainly 6 units along with 10 test papers to judge your knowledge which help you to solve chemical reactions of organic chemistry and remove the fever of mechanism of organic reactions.Preface The guiding principle in writing this book was to create a textbook for students.in 9122057123 (iii) . Organic chemistry is very easy and conceptual subject and need proper understa nding of the basics a nd stretegy to solve the questions in corret manner. hoping they don’t run out of memory. especially because it is relatively easy to frame a very large number of multiple-choice questions and theory of the subject. Suggestions from readers for the improvement of the book are welcome. This book a lso covers a ll the questions of AIEEE. IIT-Mains. IIT-Advanced. In this book we mixed all our teaching experience of 11 yea rs a long with theora tica l a nd experimenta l knowledge to generate a hand book for all students to reason their way to a solution rather than memorize a multitude of facts.co. We would like to thank the editors and production staff for their efforts in bringing out the book. in 09122057123 (iv) . We have written this book to remove the fever of organic chemistry from mind of students. this edition has been presented before you with efforts to make it error free. if you find any. senior Chandra Vijay Rao and Dr.co. please let us know so they can be corrected in future printing. 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. Nizamuddin sir. Any that remain are our responsibility. Finally. We want to make this book as user friendly as possible. Vijay Pratima Mittal madam. and we will appreciate any comments that will help us to achieve this goal in future editions. Ajnish Gupta & Bharti Gupta Professors of Organic Chemistry
[email protected] We are tha nkful to all the teachers who taught us during the concept building session of our life specially Dr. (MTC) 52 Comprehension type questions 54 Integer type questions 59 : Objective approach 81 Exercise 03 : World of competition 60 Answer 83 : World of competition Unit 2 : Oxidation.Table of Contents Page No. (MTC) 120 Comprehension type questions 123 Integer type questions 126 : Objective approach (v) 154 . Reduction & Alkane 84 Exercise 01 : Subjective approach 85 Answer 143 : Subjective approach Exercise 02 : Objective approach 92 Single correct questions (SCQ) 92 Multiple correct questions (MCQ) 112 Assertion/reason type questions (A/R) 118 Answer Match the column type ques. 01 Unit 1 : Alkene and Alkynes Exercise 01 : Subjective approach 02 Answer 68 : Subjective approach Exercise 02 : Objective approach 08 Single correct questions (SCQ) 08 Multiple correct questions (MCQ) 41 Assertion/reason type questions (A/R) 50 Answer Match the column type ques. alcohol & ether 283 Exercise 01 : Subjective approach 284 Answer 385 : Subjective approach Exercise 02 : Objective approach 290 Single correct questions (SCQ) 290 Multiple correct questions (MCQ) 341 Assertion/reason type questions (A/R) 348 Answer Match the column type ques.Exercise 03 : World of competition 129 Answer 156 : World of competition 157 Unit 3 : Aromatic compounds Exercise 01 : Subjective approach 158 Answer 242 : Subjective approach Exercise 02 : Objective approach 172 Single correct questions (SCQ) 172 Multiple correct questions (MCQ) 194 Assertion/reason type questions (A/R) 199 Answer Match the column type ques. (MTC) 350 Comprehension type questions 352 Integer type questions 356 : Objective approach (vi) 397 . (MTC) 202 Comprehension type questions 204 Integer type questions 207 : Objective approach 268 Exercise 03 : World of competition 210 Answer : World of competition 270 Test-1 : Hydrocarbon & Benzene derivatives 272 Answer : Test-1 282 Unit 4 : Alkyl halide. Exercise 03 : World of competition 360 Answer : World of competition 400 Test-2 : Alkyl halide. Carboxylic acid and Derivatives Answer : Test-3 510 521 Unit 6 : Biomolecules. POC and 522 Physical properties Exercise 01 : Subjective approach 523 Answer 578 : Subjective approach Exercise 02 : Objective approach 525 Single correct questions (SCQ) 525 Multiple correct questions (MCQ) 540 (vii) . (MTC) 449 Comprehension type questions 452 Integer type questions 458 : Objective approach 507 Exercise 03 : World of competition 461 Answer : World of competition 509 Test-3 : Aldehyde. alcohol & ether 402 Answer : Test-2 413 Unit 5 : Aldehyde. Ketone. Ketone. Polymer. Carboxylic acid 414 and Derivatives Exercise 01 : Subjective approach 415 Answer 484 : Subjective approach Exercise 02 : Objective approach 424 Single correct questions (SCQ) 424 Multiple correct questions (MCQ) 442 Assertion/reason type questions (A/R) 446 Answer Match the column type ques. co.in (viii) . Carboxylic acid and Derivatives 624 Test-8 : Mixing of chapters in organic reactions 635 Answer : Test-4. (MTC) 547 Comprehension type questions 549 Integer type questions 551 : Objective approach 588 Exercise 03 : World of competition 554 Answer : World of competition 590 Test-4 : Biomolecules 592 Test-5 : Reduction. Oxidation. Hydrocarbon. 7. Alkyl halide alcohol & Ether 603 Test-6 : Reduction. & Derivative. 8 645 Organic Chemistry is easy by www. Oxidation. 6. Ketone. Alkyl halide alcohol & Ether 613 Test-7 : Aldehyde.Assertion/reason type questions (A/R) 545 Answer Match the column type ques. Hydrocarbon & Derivative. 5. CoachMe.in 1 .co.Alkene & Alkyne Unit 1 Alkene and Alkynes Objective This unit give you a n understa nding of “ Genera l Orga nic chemistry of alkene & Alkyne” and covers following topics: Reaction of HX Reaction of H2 O/H+ Reaction of ROH/H+ Reaction of X2 Reaction of X-X’ Reaction of NOX Reaction of HOX Oximercuration-Demercuration Alkoxymercuration-Demercuration Hydroboration-Oxidation Organic Chemistry is easy by www. Then you should compare your answers or suggestions with ours before going to next chapter. That is why we are first providing you some questions so that your understanding about the topic should be increased. You have to understand the principle because the only way to tackle organic chemistry is to learn to work it out. 2. Here starts the first set of 55 questions 1. Comment over it by taking simple alphabets without any reaction. Na me the types of reagent generally we encounter in organic chemistry.co. you need to solve all the problems without looking the answers.in . 2 Organic Chemistry is easy by www. The problem would be of little use to you when you could not check your answers. You can learn trivial things like name of compounds but that doesn’t help you to understand the principle behind the subject. What are the general types of organic reactions.CoachMe.Alkene & Alkyne Exercise 01 Subjective Approach You can’t learn organic chemistry because there’s too much of it. These problems should be set you on your way but they are not the end of the journey as you begin your journey to understand organic chemistry. If any answer is mismatch then darken those question numbers with red pen and again have a micorscopic look over it and its theory and correct it before proceeding further. For the maximum benefit. Wha t is rea gent. 6. O O OH – . What is free radical and what a re the factors which increases the free radical formation easy in a ny molecule. How they are classified. F – O NH 3 . What is nucleophile and what a re the factors which Increases the nucleophilic character of any molecule. What is a n electrophile a nd what a re the fa ctors which increases the electrophilic nature of any molecule. Give an example which violate this rule. What is the basic concept behind Markownikoff rule. 10. 16. What is the basic difference between base. 4. Wha t is genera l hydra tion rea ction of alkene.CoachMe.in 3 . Write example of each types. 5. F – O NH 3 . Ph–O – . CH 3 –C–O – . O O OH – . What is Markownikoff rule. H 2 O 9. 12.Alkene & Alkyne 3. nucleophile and ligand. How is it importa nt in organic chemistry. Explain with example. 15. Cl – .co. Write in decreasing order of leaving group character in given molecules. H 2 O 8. What is Baeyer’s reagent. What are solvents. 14. Organic Chemistry is easy by www. Br . CH 3 –C–O – . CH 3 –S–O – – – – I . Ph–O – . Write the order of nucleophilic character in given molecule. 7. 11. Cl . What is leaving group and what are the factors which increases the leaving group character of a ny species. Br– . CH 3 –S–O – I – . 13. What is the general chemical reaction of alkene & alkyne. Give the mechanism of hydration of propene. Write 2 chemical test which can distinguish alkene from alkanes. 8 7 ICl 6 HOCl Br2 /CCl 4 HCl H2 O/H+ Br2 /H2 O 5 1 2 ii) (Ac2O)Hg/H2 O ii) NaBH4 i) BH3 ii) H2 O 2 /OH– 3 4 4 Organic Chemistry is easy by www. Explain with an example. Write the reaction as well as mechanism of addition of ICl on alkene. 27. 19. Write the reaction as well as mechanism of addition of HOCl on alkene. What is alkoxymercuration-demercuration. What is hydroboration-oxidation. 22. taking propene as a substrate. 24. What are the three methods by which water is added to alkene. Explain with an example.co. 21.CoachMe. What is oximercuration-demercuration. Write the major product of following reactions. 23. What type of change in product is observed when bromination is carried out in different conditions such as (A) Br2 / CCl 4 (B) Br2 /H 2 O (C) Br2 / NaCl (D) Br2 / CH 3OH Write the reaction using propene as substrate. taking propene as substrate. Write the reaction as well as mechanism of addition of HBr on alkene. 25.in . taking propene as a substrate. Explain with an example. Comment on the nature of hydroboration-oxidation and state whether it follows Markownikoff rule or violate it.Alkene & Alkyne 17. Write the mechanism of bromination of alkene using propene as substrate. 18. 20. 26. (A) But-1-ene (B) 3-Methylcyclohexene (C) Penta-1. Write the product formed on reaction on propene with it. What is the role of mercury sulphate in hydration reaction of alkyne along with dilute sulphuric acid. What product is obtained when propene is hea ted with chlorine at high temperature. 35. 36. 34.CoachMe. 37. Explain with an example taking propene as a substrate. What will be the major product obtained when compound ha ving conjuga tion of a lkene & a lkyne such a s pent-1-en-3-yne is treated with 1 eq. Give reaction as well as mechanism of it taking propyne as substrate.4-diene 33. Why alkenes are generally more reactive than alkyne towards any electrophilic addition reaction. Organic Chemistry is easy by www. What is NCS. Why some acids are added to the reaction chamber before adding water in the hydration reaction of alkene & alkynes. What will be the major product obtained on reaction of NBS over following substrate. What will be the major product obtained when compound having double bond & triple bond are not is conjugation such as pent-1-en-4-yne is treated with 1 eq. What is Kharasch effect or Anti-Markownikoff rule. of HCl. How general hydration of alkyne occur.4-diene (D) Cyclohexa-1. 32. 29. What is NBS. 41.Alkene & Alkyne 28. 31. Write the reaction as well as mechanism of addition of HCl on alkyne.co. What will be obtained as a product when propyne undergoes hydroboration-oxidation reaction. Write the product formed on reaction of propene with it. 30. 39. 40. Write the reaction as well as mechanism of addition of HOCl on propyne. 38.in 5 . of HCl. Write the product of bromination in different condition. What is the major product of hydroboration oxidation reaction of following compounds. 6 Organic Chemistry is easy by www. How terminal alkyne is distinguish from non-terminal alkynes.CoachMe. What is the major product of oximercuration-demercuration of following compounds. CH3 | i)(Ac 2O)Hg/H2O (A) CH3 – CH – CH = CH2 X ii)NaBH4 CH3 | i)(Ac 2O)Hg/H2O (B) CH 3 – CH – C CH Y ii)NaBH 4 44.Alkene & Alkyne 42.in . Br2 /CCl 4 Br2 /H 2 O Br2 /CH3 OH M N O Br2 /NaCl P 45. HCl i) B 2H 6 i) B2 H 6 ii) CH 3COOH 6 H O C l 7 O 2 H2 g/ ) H BH 4 Br2 O a 2 c A i i) N )i ( 1 8 ii) H 2O 2 /OH ICl 5 – 3 H 2O/H +/Hg 2+ 4 46. Write the major product of following reaction.co. CH3 | i) B2H6 (A) CH3 – CH – CH = CH 2 X ii) H2O 2 /OH– CH3 | i) B H 2 6 Y (B) CH3 – CH – C CH ii) H O /OH– 2 2 43. 50. H OH OH (D) N H 53. N (A) (B) (C) (A) H 2 C = C = CH2 (B) (C) (D) O O O 54.5-triene. Why the acid catalysed hydration of following alkene follows > the same order as that of stability of it.Alkene & Alkyne 47. Write the ma jor product of protona tion in following compounds. What will be the product of bromination of following substrate. What product will be formed when acetylene (HC CH) is heated with Fe? 48. What will be the major product of acid hydration in given compounds. 52. O O (A) (B) OH (C) HO (D) Ph Ph Organic Chemistry is easy by www. Why electrophilic addition of 1.3-diene.3-Butadiene is faster than that of But-1-ene. Write the mechanism of following interconversion. OH Ph – CH – C CH H 2O /H + O Ph – CH = CH – C – H 55. > 49.CoachMe. 51.co.in 7 . Write the structures of total isomers (excluding stereo) formed when one equivalent of HBr is added to Hexa-1. Write the structures of total isomers (including stereo) formed when one quivalent of HBr is added to Buta-1.3. I II III IV V Correct order for electrophilic addition reaction of given compound follows (A) I > II > III > IV > V (B) III > V > II > IV > I (C) III > IV > V > II > I (D) I > IV > III > II > V 8 Organic Chemistry is easy by www.co.CoachMe.Alkene & Alkyne Exercise 02 Objective Approach Single Correct Questions (SCQ) : 1.in . CH2 =CH2 I CH3 –O–CH=CH 2 II Cl–CH=CH 2 IV OHC–CH=CH 2 V CH 3 –CH=CH 2 III Correct order for electrophilic addition reaction of given compound follows (A) I > II > III > IV > V (C) II > IV > III > I > V (B) II > III > I > IV > V (D) V > IV > II > III > I O Cl O CH 3 2. Alkene & Alkyne Ph 3.in 9 . (A) III > I > II > IV (B) IV > II > I > III (C) III > II > I > IV (D) IV > III > II > I IV Organic Chemistry is easy by www. H 2 C=CH 2 CH 3 –CH=CH 2 CH 3 –C=CH2 | I II CH3 II CH 3 –C = C–CH 3 | | CH3 CH3 IV Correct order for electrophilic addition reaction of given compound follows 5.co. Ph Ph–CH=CH–Ph II I Ph–CH=CH–CH 3 III CH3 –CH=CH–CH 3 IV Correct order for electrophilic addition reaction of given compound follows (A) I > II > III > IV (B) I > III > II > IV (C) I > II > IV > III (D) II > I > III > IV 4. (A) IV > III > II > I (B) I > II > III > IV (C) III > IV > II > I (D) IV > II > I > III Cl CH=CH2 CH 3 I CH=CH 2 II CH 3 O O2N CH=CH 2 III CH=CH2 IV Correct order for electrophilic addition reaction of given compound follows 6.CoachMe. in . 3 2 I II III IV Rate of addition of Cl2 / H2O of the following alkenes is (A) IV > III > I > II (C) I > II > III > IV (B) IV > III > II > I (D) I > II > IV > III 10. (A) (C) 10 Ph Ph Ph Ph (B) OCH3 (D) CH 3 Organic Chemistry is easy by www. Incorrect order of reactivity towards electrophilic addition reaction of following compound follows (A) Ethene > Propene (B) Methoxyethene > Chloroethene (C) Phenylethene > Cyclohexylethene (D) Ethene > Ethyne 8. CH3 –O–CH=CH 2 I F–CH=CH2 II CH=CH2 CH3–CH=CH2 III IV Rate of hydration of the following alkenes is (A) I > II > III > IV (B) I < II < III < IV (C) I > IV > III > II (D) I > IV > II > III CH3 CH2=CH2 CH2=CH–CHO CH3–CH 2–CH=CH2 CH –C=CH 9.Alkene & Alkyne Correct order for electrophilic addition reaction of given compound follows (A) I > II > III > IV (B) I > II > IV > III (C) II > I > IV > III (D) II > IV > III > I 7. Which of the following reactant is most reactive towards electrophilic addition reaction with HBr.co.CoachMe. co. F3C – CH = CH2 + HCl Major product H (A) F3 C–C–CH 3 Cl (C) F3C–CH–CH 2 Cl Cl (B) F3C – CH2 – CH3 (D) F3CCH2CH2Cl Organic Chemistry is easy by www.Alkene & Alkyne HBr Major product 11. (D) CH=CH CH–CH 2 (A) Br HBr Cl Major product (B) CH 2–CH Br Br Br (C) CH=CH (D) CH=CH 14.CoachMe. CH2Br (A) (B) CH 3 Br CH3 Br (C) Br (D) HCl Major product 12.in 11 . H CH 2–CH2–Cl Cl–C–CH3 (A) (B) Cl CH2–CH3 CH2–CH3 (C) 13. OCH 3 CH3 OD CH 3 Br (C) (D) 12 CH 3 OH CH 3 .in . Z obtained in the following reaction is: CH3 HBr H2O X HBr CH 3OH Y HBr D 2O Z (A) OH CH 3 .Alkene & Alkyne CH 2 HBr 15. in all reaction in all reaction Organic Chemistry is easy by www.CoachMe.co. X (major product) X will be CH 2 –Br (A) (B) CH 3 (C) CH 3 Br CH 3 Br (D) Br 16. OCH 3 CH 3 (B) OH CH 3 . Major product X. Y. OD CH 3 . CoachMe. The product of following reaction can be : OH HBr CH=CH 2 H3 C CH 3 (A) H3 C OH OH (B) CH3 CH 3 CH 3 H3 C (C) O CH2 (D) O CH 3 Organic Chemistry is easy by www.in 13 .Alkene & Alkyne 17. Which of the following is/are the major product(s) of the following reaction? CH 3 CH= C HBr ? CH3 CH 3 CH=CH (A) CH2 –C Br (B) Br CH 3 CH 3 CH=C (C) CH=C (D) Br Br 18. In which of the following alkenes will a hydrogen shift occur upon addition of HBr? (A) (B) (C) (D) 19.co. CoachMe.in Br . HBr CH2 –Br (A) (B) CH 3 Br (C) CH 3 (D) Br HCl 22. CH 3 X (major product) (A) (B) CH 3Cl Cl (C) Cl (D) Cl CH3 HCl 23.co. Ph–CH=CH–CH 3 The major product of given reaction will be Cl (A) Ph–CH –CH=CH 2 3 (C) Cl (B) CH=CH–CH3 Cl Ph–CH–CH 2 –CH 3 (D) Cl CH=CH–CH3 CH 3 21. OH X (major product) Major product X will be Cl Cl (A) (B) Cl Cl (C) 14 (D) Organic Chemistry is easy by www.Alkene & Alkyne HCl 20. 2-Dichlorocyclohexane Organic Chemistry is easy by www.2-Dichlorocyclohexane (D) trans-1.3-Dichlorocyclohexane (C) cis-1. HCl X The major product ‘X’ in the given reaction will be (A) cis-1. How many transition state and intermediate will be formed during the course of following reaction.3-Dichlorocyclohexane (B) trans-1.in 15 .co. HBr The product(s) of the following reaction can best be (A) A racemic mixture (B) A single enantiomer (C) A pair of diastereomers (D) A single meso compound Cl 28. Which of the following reaction results in the formation of a pair of diastereomers on treatment with HBr (C) (D) Ph 26.CoachMe. Which of the following reaction results in the formation of pair of enantiomers on treatment with HBr (A) (B) (A) (B) (C) (D) O 25. Br HBr (A) 3 TS & 3 intermediate (B) 4 TS & 3 intermediate (C) 3 TS & 2 intermediate (D) 3 TS & 4 intermediate Et Me 27.Alkene & Alkyne 24. 5-dichloropentane (C) 2.4-dichloropentane (B) 1. Cl The intermediate formed in given reaction will be (A) 34. (B) (C) (D) Cl HCl The carbocation which is not formed at all in given transformation reaction is (A) 16 (B) (C) Organic Chemistry is easy by www.CoachMe.in (D) .co. Which reaction will occur at the fastest rate.4-pentadiene with excess HBr. Which reaction has the lowest ΔG or activation energy? (A) HBr (B) HBr (C) HBr (D) HBr HCl 33. HBr Br HBr (A) (B) Br (C) HBr Br HBr (D) Br 30. (A) 1. .Alkene & Alkyne 29.4-dichloropentane (D) 4-chloro-1-pentene 31. Which energy dia gra m best describes the electrophilic addition of HBr to alkenes? (A) (B) (C) (D) 32. Predict the major product of the reaction of 1. in 17 . Which of the following energy profile best represents above reaction Ep Ep (A) (B) Overall reaction Overall reaction Ep Ep (C) (D) Overall reaction Overall reaction Organic Chemistry is easy by www. ? Which reaction mechanism is most likely to occur during this reaction.Alkene & Alkyne HCl 35.CoachMe. Cl H+ (A) Cl Cl (B) H+ (C) H (D) Cl + Cl H+ Cl Cl Cl H+ 36.co. II is minor dil.CoachMe.co. What is/are the product(s) from the following reaction? CH 3 + HCl CH 3 Cl ? CH 3 Cl (I) (A) I only (B) II only (C) I is minor.H 2SO 4 40. II is major (D) I is major.H SO 38. 4 2 CH 3 HO OH OH (B) (A) 39. CH 3 (D) CH=CH–CH3 X (major product) Major product X will be : (A) only (B) only CH2–CH–CH3 OH (C) (A) and (B) 18 CH–CH 2–CH3 OH (D) OH CH2–CH 2–CH3 Organic Chemistry is easy by www. (II) (C) OH (D) dil.Alkene & Alkyne 37.H SO 2 4 X (major product) Major product X is : CH 3 CH 3 OH (A) (B) OH OH OH CH 3 (C) dil.in . Ph – CH2 – CH = CH2 (A) (C) Ph–CH–CH 2 –CH 3 OH Ph–CH–CH–CH 3 (B) Ph–CH–CH–CH 3 H OH (D) Ph – CH2 – OH OH OH H 2O/H + 42.in 19 .co.Alkene & Alkyne dil. The intermediate formed in given reaction will be (A) (B) O (C) (D) OH H dil.H 2 SO 4 41.H SO 43. H 2SO 4 CH3 OH (A) CH 3 –C–CH 2 –CH 3 H (B) CH 3 CH 3 C–CH3 CH3 H CH 3 –CH–CH 2 –CH2 –OH (C) CH 3 –C OH (D) HOCH 2 –CH CH–CH3 CH 3 H Organic Chemistry is easy by www. CH 3 –CH–CH=CH 2 NO 2 dil.CoachMe. 2 4 NO 2 (A) HO OH (B) NO 2 NO2 HO OH (C) (D) NO2 44. CCl 4 HO X (major product) Major product X will be (A) (C) OD H (B) H 2 O/H + 48.Alkene & Alkyne CH 3 45. H CH 3 Br 2 C=C H (X) Product. Value of X is: (A) 0 (B) 1 (C) 2 (D) 3 H+ 46.CoachMe. (B) CH 3 OD H (C) D OH (D) X (major product) The major product X of the given reaction will be OH (A) (C) 20 OH (B) OH (D) OH Organic Chemistry is easy by www.in OH .co. CH 3 OH X (major product) D (A) O (D) OH D2O/H + 47. Which of the following is among the major products of the reaction of (E)-3-methyl-2-pentene with BH3 in THF followed by the addition of H 2O2//HO– ? OH H Et (A) H Me (B) Me H (C) H Et Me OH H H (D) Et Me Et 50. Product (A) is: Br H CH 3 O CH 3 CH 3 O Br Organic Chemistry is easy by www. Me H Me Me OH H OH Me OCH3 (A) CH3 OH / H+ (B) CH3 CH2 OH / H+ (C) H2 O / H+ (D) HOCl / H+ x CH 3 CHCH2 CH3 x will be : 51.Alkene & Alkyne 49. CH 3 (A) (C) C=C H Br2 C(CH3 )2 CH 2 OH CCl 4 Br CH 3 CH3 O CH 3 (B) CH 3 Br CH 3 O CH 3 (D) H (A).co.CoachMe. CH3 CH = CHCH3 OCH 2 CH3 (A) CH3 OH / H+ (B) CH3 CH2 OH / H+ (C) H2 O / H+ (D) HOCl H 52.in 21 . co. HO– (A) CH 3 H H OH CH 3 54.CoachMe. CH3 OH H H (B) O (C) CH 3OH/H CH 3 H3 C CH 3 H H H CH 3 H H CH 3 (D) + X (major product) The major product X will be CH 3 CH 3 O (A) H C 3 OCH3 CH 3 (C) (B) CH 3 H3 C OCH3 OCH 3 CH 3 OCH3 (D) H3 CO H3 C 55.in CH 2 –CH2 –CH 3 .THF 53.Alkene & Alkyne CH3 H (1) BH 3 . Ph–CH=CH–CH3 CH 3OH/H + OCH3 CH 3 X (major product) The major product X will be (A) (C) 22 Ph–CH2 –CH–CH 3 OCH3 Ph–CH2 –CH 2 –CH 2 OCH3 (B) Ph–CH–CH 2 –CH 3 OCH 3 (D) H3 CO Organic Chemistry is easy by www. Product of the reaction is: (2) H 2O 2 . (A). Alkene & Alkyne 56. Br (D) Br Br /H O 2 2 58. Br2 Br Br (A) (B) Br Br Br (C) Br (D) Br Br Organic Chemistry is easy by www.co. H Product of above reaction is: (A) meso (B) racemic mixture (C) diastereomer (D) structural isomer 60. cis-2-Butene CH 3 CH 3 CH 3 CH 3 H H OH OH H3 C H C OH 3 Br Br H (C) Br (A) H (B) Br H (D) HO H CH3 CH3 H H H Br2 CCl 4 59.in 23 . Which reaction intermediate is formed when Br2/CCl4 reacts with cyclohexene? Br (A) (B) Br (C) . What is the major product of the following reaction? CH 3 Br2 + H 2O X (major product) The major product X will be CH 3 Br (B) OH (A) CH 3 CH 3 Br (D) OH (C) Br CH 3 OH 57.CoachMe. Which compound on reaction with bromine give meso-2. Br2 X (major product) Major product X will be H Br N N (A) (B) Br (C) Br2 N (D) Br Br Br OH 63. N Br Br X (major product) Major product X will be (A) O Br Br Br (B) OH Br (C) O Br (D) O 64.3Dibromobutane as a product. (A) 24 (B) (C) Organic Chemistry is easy by www.in (D) .CoachMe.co.Alkene & Alkyne 61. What is/are the product(s) from the following reaction? + Br2 /CCl 4 ? Br (I) (II) Br Br (III) Br (IV) Br (A) I and II (B) I and III Br Br Br (C) I and IV (D) II and III H N 62. Which of the following is most reactive toward bromination? (A) OCH3 (B) (C) (D) CH 3 68.CoachMe. Value of X is: (C) 2 (D) 3 Organic Chemistry is easy by www.Alkene & Alkyne CH 3 H 65.in 25 .co. Br2 C2H 5 CCl 4 (Z) Br Br (A) H Br Br Br Br H Br Br (C) Br (D) H C Br (B) Br 3 C2H 5 H5 C 2 H H5 C 2 Br H5 C 2 Br CH 3 CH 3 CH 3 H Br2 CCl 4 66. (stereoisomer) ( ) Identify product’s: Et Et Br (A) Br Br (B) Br Br Et Br (C) Br Br (D) H 67. H C=C H (A) 0 Cl CH3 Br2 CCl 4 (B) 1 (X) products. Br OH Br NH2 X (major product) Major product X will be Br Br (A) OH Br (B) OH Br (C) 26 O (D) O Organic Chemistry is easy by www.Alkene & Alkyne 69.in Br Br– . Which of the following species is an intermedia te in the reaction shown below? Br Br2 /H 2O OH (A) (B) Br+ Br2(1 eq) 70.co.CoachMe. (C) O NH 2 (D) + O H X (major product) Major product X will be Br N (A) N (B) H H Br Br (C) (D) NH 2 Br2 (1 eq) 71. (A) CH3 OH / H+ (B) CH3 CH2 OH / H+ (C) H2 O / H+ (D) HOCl / H+ Organic Chemistry is easy by www. X (major product) Major product X will be O O S (A) O O O (B) S O Br Br SO 3 H (C) (D) Br Br SO 3H Br Cl OH 74.CoachMe.co.Alkene & Alkyne COOH Br2 72.in 27 . X (major product) Major product X will be O O O (A) O (B) Br Br COOH O O (C) (D) Br Br Br SO 3H Br2 73. The intermediate formed in halolactonization reaction is (A) Carbocation (B) Cyclic halonium ion (C) Carbanion (D) Free radical COO – I 2 /NaHCO 3 CH 2Cl 2 77. (B) It is the organic reaction that form acyclic amide by the addition of an oxygen and iodine across a carbon-carbon double bond. (C) It is the organic reaction that form acyclic ester by the addition of an oxygen and iodine arcoss a carbon-carbon double bond. 76.Alkene & Alkyne 75.in CH 3 CH 3 .co. CH3 CH 3 X (major product) X (major product) O O O (A) O H I–H 2 C CH 3 CH 3 (B) H O O O (C) 28 O H IH2 C CH 3 CH 3 I–CH 2 CH 3 CH 3 (D) H CH 2 I Organic Chemistry is easy by www.CoachMe. Which statement is correct for iodolactonization reaction (A) It is the organic reaction that form a lactone by the addition of an oxygen and iodine across a carbon-carbon double bond. (D) It is the organic reaction that form lactum by the addition of a n oxygen and iodine arcoss carbon-carbon double bond. Alkene & Alkyne 78.CoachMe. ii) I2 . O OH i) NaHCO 3 79. Which is incorrect among these? COOH (A) Ph O I2 /NaHCO 3 O CHCl 3 0°C. 6H COOH (B) Ph Ph I O I2 MeCN 0°C. 0°C O X (major product) Major product x will be O O O O (B) I (A) I O O O O O I (C) I (D) O 80. 24H O Ph I (C) Formation of cis product is kinetic product while trans product is thermodynamic product.in O Br 29 .co. (D) Formation of cis product is thermodynamic product while trans product is kinetic product. OH Br2 CH 2Cl 2 X (major product) Major product X will be (A) Br Br (B) O (C) Br OH O Br (D) Organic Chemistry is easy by www. KI. (A) In 1 st step. CH 3 –CH–CH=CH2 84. NaBH4 reduce –HgOAc group & attached H. (D) Carbocation is formed in this reaction.in CH 3 . Which of the following sta tement is wrong a bout oxymercuration-demercuration reaction of alkene.co.Alkene & Alkyne 81. Which will not be the product of given reaction OH (A) Br2 /H 2O H Br O OH (C) OH (B) (D) Br OH i) Hg(OAc) 2 /H 2O ii) NaBH 4 82. (B) In 2 nd step.CoachMe. (C) The net reaction is a ddition of wa ter according of markownikoff rule. O H Br OH OH The intermediate of reaction will be (A) (B) O (C) Hg–O–C–CH 3 (D) HgOCOCH 3 83. CH3 (i) Hg(OAc)2 /H 2O (ii) NaBH 4 OH (A) CH 3 –C–CH 2 –CH 3 H (B) CH 3 (C) 30 CH 3 –CH–CH 2 –CH2 –OH CH3 CH 3 –C OH C–CH 3 CH 3 H (D) HOCH2 –CH CH 2 –CH3 Organic Chemistry is easy by www. Hg(OAc)2 & H2O adds to C=C double bond. ii) NaBH 4 (C) H OH D H (D) D H X (major product) Major product X will be OH (A) O (B) O (C) O (D) Organic Chemistry is easy by www. (2 ) NaBH 4 + OH – (A) (B) OH OH (C) (D) all of these OH CH 3 C–CH=CH2 86. H (1) Hg(O 2CCH 3 )2 . H 2 O (2 ) NaBH 4 + NaOH CH3 H C C – CH3 (A) H CH3 H OH CH3 H C C – CH3 (C) C H (B) C – CH3 H CH3 C–CH2 –OH (D) CH3 OH H Hg(OAc)2 /H 2O NaBD4 87.Alkene & Alkyne (1) Hg(OAc)2 /THF– H 2O 85. OH (A) H H D (B) OH H OH D OH i ) Hg (OAc)2 88.in OH 31 .CoachMe.co. X (major product) Major product X will be O O HgOAc (A) OAc (B) O OAc HgOAc O OAc (C) (D) HgOAc HgOAc OAc (i) BH3 –THF 91.CoachMe.in .Alkene & Alkyne 89. (A) (B) (C) (D) O Hg(OAc) 2 /ACOH 90.co. Which of the following alkene will give Methylcyclohexanol on oxymercuration-demercuration reaction. (ii) H2O2/OH - (A) CH3HO CH 3 (B) H HO H OH (C) CH3 H H 32 OH (D) CH3 H H Organic Chemistry is easy by www. co.Alkene & Alkyne 92. (B) Formation of 5 membered cyclic transition state. (C) Formation of 4 membered cyclic transition state (D) Formation of 3 membered cyclic transition state (i) BD 3 – THF (ii) H 2O2 / OH¯ 94. CH 3 –CH–CH=CH 2 CH3 (i) BH 3 –THF (ii) H 2O 2 /OH OH (A) CH 3 –C–CH 2 –CH 3 H (B) CH 3 –C CH 3 (C) CH 3 –CH–CH 2 –CH2 –OH CH3 OH C–CH 3 CH 3 H (D) HOCH2 –CH CH 2 –CH3 CH 3 93. (A) H H D (B) OH H OH D H OH (C) H H (D) H OH H H D BH 3 . H 2O 2 . Hydroboration oxidation reaction of alkene follows via (A) Formation of 6 membered cyclic tranition state. OH – (A) (C) OH (B) OH (D) OH Organic Chemistry is easy by www.in 33 . THF 95.CoachMe. CH 3 –CH–CH=CH 2 HBr –20°C HBr 40°C Br (A) Both the major product A and B are Hydrobora tion- CH3–CH=CH–CH2–Br (B) (A) Kinetically controlled product (B) Thermodynamically controlled product (C) A is thermodynamica lly controlled & B is Kinetically controlled. H 2O 2 /OH – (A) (C) X (major product) H (B) D D (D) OH X will be OH D H OD X OH 97. (D) Oxymercura tion-demercura tion.CoachMe. (D) A is kinetically. Y OH Z OH X. 98. Z reactions are respectively called as (A) All is simply hydration reaction. Hydroboration-oxidation. B is thermodynamically controlled 34 Organic Chemistry is easy by www. Y. (C) Acid hydration. oxidation.co.in . Oxymercura tion-demercura tion.Alkene & Alkyne BD 3 /THF 96. (B) Acid hydra tion. Hydroboration-oxidation oxymercuration demercuration. acid hydration. Cl Cl (A) (C) (B) (D) Cl Cl 100.co.in 35 . HBr / R2O 2 CH=CH CH–CH2 (A) (B) CH 2 –CH Br Br Br Br CH=CH (C) (D) CH=CH 101.CoachMe. What is the major product of the following reaction? CH 3 HBr Peroxide ? Br (A) CH 3 (B) CH 3 (C) (D) Br CH 2 Br CH 3 Br Organic Chemistry is easy by www.Alkene & Alkyne HCl (1 eq) 99. (B) I Cl Cl (D) I HOCl The intermediate of given reaction will be (A) O (B) Cl H (C) 105. CH 2 CH 2 CH 3 + HBr (D) CH 2 CH 2 CH 3 + HBr I – Cl The intermediate of given reaction will be (A) (C) 104.in (D) .co. (A) (C) 103. Cl (D) OH NBS The intermediate of given reaction will be (A) 36 (B) (C) .CoachMe. CH 2 CHCH 3 + HBr Br CH 2 CHCH 3 + HBr Br (B) . Organic Chemistry is easy by www. Which of the following is a step in the mechanism of the reaction shown? CH 2 =CHCH 3 + HBr Peroxide CH 2 CH 2 CH 3 Br .Alkene & Alkyne 102. Alkene & Alkyne 106. NOCl The intermediate of given reaction will be (A) (C) (B) NO N NO (D) Cl O 107. Cl–CN The intermediate of given reaction will be (A) (C) (B) Cl CN (D) Cl N C NBS 108. CH 3 –CH=CH 2 (A) CH 3 –CH2 –CH 2 –Br (B) CH 2 –CH=CH 2 Br (C) CH 3 –CH–CH 3 Br (D) CH 3 –CH–CH 2 Br Br Cl /CCl 2 4 109. trans-2-pentene CH 3 H Cl (A) Cl H C2H 5 CH 3 CH3 CH3 H Cl H C 2 H5 H C 2 H5 (B) H Cl (C) Cl (D) Cl H H C2H 5 H Cl Organic Chemistry is easy by www.CoachMe.co.in 37 Alkene & Alkyne 110. Predict the product of the reaction of 1-pentyne and excess HCl in the presence of hydrogen peroxide. (A) 1,1-dichloropentane (B) 1,2-dichloropentane (C) 2,2-dichloropentane (D) 2-chloro-1-pentene OH 111. CH 3CHCH 2 CC CH3 (A) CH H 2O.H 2SO 4 HgSO 4 CH3 O CH 3 –CH–CH 2 –C=CH–C–H CH 3 CH3 OH O (B) CH 3 –CH–CH 2 –C CH 3 C–CH 3 CH 3 OH (C) CH 3 –CH–CH 2 –C – C=CH 2 CH 3 CH 3 OH OH (D) CH 3 –CH–CH 2 –C–CH=CH CH 3 CH 3 OH – BH3 , THF H2O 2 /OH 112. CH 3 CH 2 CH 2 C CH (A) CH3 CH2 CH2 CH2 – CHO (B) CH 3 CH 2 CH 2 CCH2 O (C) CH3 CH2 CH2 CHO (D) CH 3 CH 2 C–CH2 CH 3 O 38 Organic Chemistry is easy by www.CoachMe.co.in Alkene & Alkyne Br2 (1 eq.) 113. CH2 = CH – CH = CH – CH = CH2 (60–80°C) X Major (A) BrCH2 –CH=CH–CH(Br)–CH=CH 2 (B) BrCH 2 –CH=CH–CH=CH–CH 2 Br (C) CH2 =CH–CH(Br)–CH(Br)–CH=CH2 (D) BrCH2 –CH(Br)–CH=CH–CH=CH 2 HCl (1 eq) 114. (A) Cl (B) 115. C3 H7 C CH Cl HBr peroxide (C) Cl (D) Cl ‘X’ X is - (A) C3 H7 CH = CHBr (B) C3 H7 CBr = CH2 (C) C 3 H 7 CBr C – Br (D) C3 H7 CH2 –CHBr2 | H C 116. CH Br2 , H 2O Br O C (A) Br (C) CH CH 2 Br2 (B) Br CH C C (D) Br C CH Organic Chemistry is easy by www.CoachMe.co.in 39 H 2 O (C) 1. CH2 = CHCHOHCH = CHMe (A) CH2 = CHCHOHCH2 CH(OMe)Me (B) CH2 = CHCH = CHCH(OMe)Me (C) CH2 = CHCH = CHCH2 Me (D) CH3 – CH (OMe) CH = CHCH(OMe)Me 118.CoachMe. What is the kinetic product for the following reaction? CH 3 + HCl ? CH 3 Cl CH 3 Cl CH 3 (A) (B) (C) (D) CH 3 Cl Cl 119. Hg(O2 CCF3 )2 .in . NaBH 4 40 Organic Chemistry is easy by www.Alkene & Alkyne MeOH H 2SO 4 117. BH 3 .co. NaBH 4 (D) 1. Hg(OAc)2 . CH 3OH 2. H 2 O/THF 2.What reagents can best be used to accomplish the following transformation? OH (A) 1. THF 2. H 2 O 2 (B) H . HO – . What is the major organic product of the following reaction? Hg 2+ CH H SO 2 4 H O (A) (B) OH H (C) H O H (D) H HO 120. co. Which of the following compounds will give same major product on acid catalysed hydration CH 3 (A) CH 3 Ph–C–CH=CH 2 Ph–CH–C=CH 2 (B) CH 3 CH 3 (C) Ph C=C CH 3 Ph CH 3 CH 3 (D) CH 3 CH 3 CH C=CH 2 123. The a lkenes which a re more rea ctive than ethene for electrophilic addition reaction are (A) CH2 =CH–Cl (B) CH3 –O–CH=CH 2 (C) CH3 –CH=CH 2 (D) CH2 =CH–CHO 122.CoachMe.in 41 . (A) (B) CH 2 =CH–CHO (H Cl(g)(–10°C) Cl CH 2 =CH–COOH H 2 O/H 2 SO 4 CH 2 –CH2 –COOH OH CH 3 (C) CH 2 –CH 2 –CHO CH 3 –C=CH–C–CH 3 CH 3OH H 2SO 4 CH 3 CH3 –CH–CH – C –CH 3 O (D) CH 3 –CH=CH–OCH3 OCH3 O CH 3OH/H + CH 3 –CH2 –CH–OCH3 OCH 3 Organic Chemistry is easy by www.Alkene & Alkyne Multiple Correct Questions (MCQ) : 121. The correct products have been reported in reactions. H2 O 125. THF–H2O 2.in . (F) and (G) a re formed via free radical. OH– (B) (I) is 1. H . THF–H2O 2. 2. NaBD4 (II) is D+/H2O (III) is 1.CoachMe.co. Hg(OAc)2. THF–B2D6. Identify the reagents. OH– (C) Products (E). 2. THF–B2D6. carbocation and four-centre transition state respectively. H2O2. (II) and (III) respectively as shown below. carbocation and cyclic carbonium ion intermediate respectively. (I) (E) CH(OH)CH2 D (P) CH=CH 2 (II) (III) OH (F) CH2 D CHDCH 2 OH (G) (A) (I) is D+/H2O. Three different alcohols (E). (F) and (G) are formed via mercury-bridged carbocation. H2O2. NaBD4 (III) is 1. (F) and (G) are synthesised from the same alkene (P) by using three different reagents (I). Hg(OAc)2. Possible products of the reaction will be OH (A) OH (C) 42 OH (B) OH (D) Organic Chemistry is easy by www. (D) Products (E).Alkene & Alkyne 124. (II) is 1. racemic mixture of products is formed? (A) (B) (C) + Br2 –CCl 4 FeCl 3 + Br2 –CCl 4 + Br2 –CCl 4 FeCl 3 FeCl 3 (D) CH 3 –CH=CH2 + Br2 –CCl 4 FeCl 3 Organic Chemistry is easy by www.Alkene & Alkyne 126. In which of the following reaction(s).in 43 .CoachMe. major product is formed by the cyclic intermediate of reactive intermediate? (A) + HCl (B) + Br2 –H2 O (C) + (CF3 COO)2 Hg (D) H 2O NaBH 4 + HBr 127. Which of the following is correct sta tement a bout oxymercuration-Demercuration(A) In the I st step oxymercuration occurs i.e. wa ter & Hg(OAc)2 add to double bond (B) In the IInd step demercuration occurs i. In which of the following halogen addition reaction. (C) The net rea ction is addition of wa ter a ccording to Markonikoff rule (D) Rearrangement takes place 128. NaBH4 reduces –HgOAc group to hydrogen.e.co. 3. What are the expected product(s) in the following reaction? hv + NBS CCl 4 (NBS=N-bromosuccinimide) Br (A) 44 Br (B) Br (C) (D) Organic Chemistry is easy by www.2. (C) Alkynes decolourise Br2 water (D) Addition of HBr to alkynes in presence of peroxide proceeds via Anti-Markownikoff’s rule 131. (B) Alkynes are less reactive than alkenes towards EAR. Consider the following a ddition reaction on a pure enantiomer of the shown bromoalkene.CoachMe. Cyclic intermediate is formed. Cyclic intermediate is formed. When But-2-yne is brominated.3-Tetrabromobutane (B) Q will be Butan-2-one (C) In the formation of P.in Br .co. P is formed. then Q is formed. When But-2-yne is reacted with HgSO4 + H2SO4. (D) In the formation of Q. CH 3 H Br + HBr CH=CH2 Products(s) What is/are true regarding products of the above reaction? (A) Four stereoisomers of products of the above reaction? (B) A pair of enantiomers and a meso-dibromide are formed (C) Only a pair of diastereomers are formed (D) One of the product is meso-dibromide 130.Alkene & Alkyne 129. 132. Identify the correct statement/statements : (A) Alkynes are more reactive than alkenes towards EAR. Which statement is correct form (A) P will be 2. I is the major product (B) At room temperature.in 45 .co.0 equivalent at HBr of –80° C (C) I gives 2 . when reacted with excess of HBr at very low temperature (D) Both have same length of C=C double bonds Organic Chemistry is easy by www.3-butadiene. (II) is/are CH2 =C=CH–CH3 (I) CH2 =C–CH=CH 2 (II) (A) I ha s perpendicular pi planes while II has para llel pi planes (B) Both gives the same product on adding 1.2 -dibromobuta ne while II gives. II is the major product (C) Both of the products I and II a re a lways formed in comparable amounts (D) Product I isomerises into II on heating above 40°C 135.Alkene & Alkyne 133. Predict products(s) in the reaction + HBr Br H (A) (B) Kinetically controlled Br Br Kinetically controlled Br (D) Thermodynamically controlled (C) Thermodynamically controlled 134.3-dibromobutane.CoachMe. The correct statement(s) regarding following reaction is/are CH2 =CH–CH=CH 2 HBr CH 2 =CH–CH–CH3 CH 2 –CH=CH–CH 3 I Br Br II (A) At –80°C. The correct sta tement(s) regarding 1. 2.2-buta diene(I) a nd 1. Alkene & Alkyne 136.in Br2 . In which case rearrnage product will be major one. (A) Halogenation (B) Acid hydration (C) Oxymercuration-demercuration (D) Hydroboration-oxidation 139. (A) (C) 46 CH 3OH/H H 2O/H + (B) HBr + (D) Ph Organic Chemistry is easy by www. Which statement is/are correct for hydroboration oxidation (A) It is the addition of water over alkene (B) It proceeds via formation of 4 membered cyclic TS.CoachMe. Addition of water over alkene occur via (A) H2O/H+ (B) Hydroboration-oxidation (C) Oxymercuration-demercuration (D) Alkoxymercuration-demercuration 137. Cl (A) HOCl NO NOCl (B) OH Cl I (C) I–Cl CH 3OH H (D) + OCH3 Cl 140. 138. In which case product is correct. In which case carboca tion is not formed a s a reaction intermediate on reaction over alkene.co. (C) It follows Markowniff rule (D) Hydrobora tion oxida tion over propene lea ds to propan-1-ol as major product. 3-butadiene. Which of the following descriptors applies to the kinetic product? (A) 1. Among the following carbocations.CoachMe.2 product (B) least stable with less substituted alkene (C) formed fastest at low temperature (D) bromide attack at more substituted site 143.THF/H 2 O 2 –OH– (C) Hg(OAc)2 . A (A) H 2 O/H + CH 3 CH–CHCH 3 OH . Reagent A may not be: (B) BH 3 . select the possible intermediates in that reaction? (A) (CH 3 )3 C C HCH2 Cl (B) (CH 3 )3 C C HCH3 (C) (CH 3 )2 CC(CH3 )2 | Cl (D) (CH 3 )2 C CH(CH 3 )2 142. Which of the following a lkenes yield(s) 3 -bromo-3 methylpentane as the major product upon addition of HBr? (A) (B) (C) (D) CH 3 CHCH=CH2 144. one product is called the kinetic product and the other is called the thermodynamic product.3-dimethyl-1-butene yields two products.co.in 47 . In the addition of HBr to 1.H 2 O/NaBH 4 (D) BH 3 . Addition of HCl to 3.THF/H 2 O 2 –AcOH Organic Chemistry is easy by www.Alkene & Alkyne 141. one of which has a rearranged carbon skeleton. HOOC Br2 CCl 4 (P) HOOCCH(Br)CH(Br)COOH (X) Br HOOC 2 COOH CCl 4 HOOCCH(Br)CH(Br)COOH (Q) (Y) The correct statements with respect to the above pair of reactions are that (A) the reactions are stereospecific (B) (X) is meso and (Y) is racemic mixture (C) (X) is racemic mixture and (Y) is meso (D) each of (P) and (Q) gives a mixture of (X) and (Y) OH 147. Which series of reactions will not achieve the following transformation? Br 1 2 Cl Cl (A) Cl 2/CCl4 Br2 (B) HBr Cl2/CCl4 (C) Cl2/CCl4 NBS/hv (D) NBS/hv Cl2/CCl4 COOH 146.Q will be O (B) P Br O (D) Q OCH 3 Organic Chemistry is easy by www.Alkene & Alkyne 145. Br2 (A) Br (C) Br 48 HBr + (P) Cl O Cl P O OCH 3 Q MeOH (Q) product P.co.in .CoachMe. CoachMe.Alkene & Alkyne 148. Select the reaction(s) that would result in the formation of 2bromopropane. peroxide (A) CH 3 CH=CH2 + HBr CCl 4 (B) CH 3 CH=CH2 + HBr hv (C) CH 3 CH 2 CH 3 + Br2 CCl 4 (D) CH 3 CH=CH2 + Br2 149.in Br 49 .co. Which of the following compounds gives the sa me carbocation on ionization? (A) Br (B) Br (C) Br (D) Organic Chemistry is easy by www. The major product of the reaction given below is : OH (A) Br (C) O Br2 H 2O ? OH (B) HO OH H (D) CH 2 –Br O Br OH CH2 –Br H 150. Assertion: Addition of HCI to 1 -isopropenyl–1 – methylcyclopenta ne yields 1 –chloro–1 . 2–trimethylcyclohexane. Reason: The intermediate carbocation for both the alkenes is same. Reason: Mechanism of reaction is CH 3 H+ CH 3 CH 3 and 152. reason is correct 151. reason is wrong (D) If assertion is wrong.2 . Assertion: The hydroboration oxidation of D D Reason: 50 gives H OH D D The syn addition of BH3 across the double bond of norbornane takes place mostly from the more accesible outside face of the double bond. Organic Chemistry is easy by www.Alkene & Alkyne Assertion / Reason type Questions (A/R) : (A) If both assertion and Reason is correct explanation of A (B) If both assertion and Reason are correct but Reason is not correct explanation of A (C) If assertion is correct. Reason: Due to formation of 1° free radical in case of 2 ethyl-1-hexene 154. Assertion: The addition of CBrCl3 in the presence of peroxides takes place faster to 2-ethyl-1-hexene than to 1-octene.CoachMe.co. 153.in . Assertion: Cl Cl CH 3 CH 3 CH3 on hydra tion give same alcohol. 2-Butyne gives Cis-2-deutero-2-butene. Assertion: 2–Bromo–1–butene reacts with HBr to give 2. 2-dichlorocyclo hexane hence easily formed. 2-dichlorocyclohexane is less sterically crowded than cis-1. Reason: The intermediate carbocation formed is stablished by +m effect of Bromine atom. H I C=C Reason: The addition of I2 to acetylene gives I H as the major product. Assertion: Acteylene is less reactive than ethylene towords electrophilic reagents. Assertion: With the use of BD 3 /THF a nd CH 3 COOH. Organic Chemistry is easy by www. Reason: The trans-1. 2-dichlorocyclo hexane. Reason: The process of reaction is H H–C C–H + H–O–Cl H–C=C HO HO–Cl Cl–C– C–H + H 2O ClOH Cl 159. Assertion: When acetylene is passed into hyochlorus acid solution dichloroacetaldehyde is formed. 158.CoachMe.in 51 . 156. 160. Reason: The same product is obtained when the reagent used is BH3 /THF and CH3 COOD. Reason: p–electron density in a triple bond is higher than that in a double bond.co.2– dibromobutane. Assertion: The addition of chlorine to cyclohexene gives a racemic mixture of trans-1. 157. Assertion: The predominant product in the addition of halogens to acetylene is the trans isomer.Alkene & Alkyne 155. Match the column: (A) HBr Peroxide (P) (B) HBr No Peroxide (Q) Br (C) HCl Peroxide (R) Cl (D) HCl CCl 4 (S) (E) NBS (T) Br Cl Br 162.co.CoachMe. Match the column: (A) HBr Proxide (P) Electrophilic-addition reaction (B) HCl Proxide (Q) Free-radical-addition reaction (R) Free-radical-substitution reaction (S) Electrophilic substitution reaction CH 3 (C) (D) 52 NBS Cl 2 /AlCl 3 Organic Chemistry is easy by www.Alkene & Alkyne Match the Column type Questions (MTC) : 161.in . Match List-I with List-II and select the correct answer using the codes given below the lists: List-I (Reaction) List-II (Reagents) (A) CH 3–CH=CH2 CH3–CHBr–CH3 (P) HBr (B) CH3–CH=CH2 CH3–CH2–CH2Br (Q) Br2 (C) CH3–CH=CH2 BrCH2–CH=CH2 (R) HBr/Peroxide (D) CH3–CH=CH2 CH3–CHBr–CH2Br (S) NBS 163. (C) Peroxide effect R.CoachMe. Cl OH Q.in 53 . Column-I Column-II Cl Cl 2 . CH 3 –CH=CH 2 H2O 2 . Cyclic intermediate Column-I Column-II Markownikoff (A) product P. Carbocation R.Alkene & Alkyne 164. (D) Mixture of stereoisomers HBr H3 C H C=C CH3 CHCl +KOH 3 H CH=CH 2 HBr S. CF3 –CH=CH 2 HBr Organic Chemistry is easy by www.hv Anti-Markownikoff (B) product Q.CCl 4 (A) P.hv (B) Br (C) CH 3OH Δ (D) H /H 2O 165.co. Rearrangement Cl Cl 2 . Free radical S. During reaction electrophile react with a lkene in ra te determining step to form carboca tion according to markownikoff rule. 166. Now answer the following questions : 54 Organic Chemistry is easy by www. Correct order of rate of Bromination: (I) (II) (III) (A) I > II > III (B) II > I > III (C) III > II > I (D) II > III > I Passage : 2 Homolytic bond fission of a covalent single bond gives rise to free radicals. free radicals are highly reactive. Owing to the presence of an odd electron. In second step carbocation react with nucleophile to give product so overall addition reaction take place.Alkene & Alkyne Comprehension type Questions : Passage : 1 In electrophilic addition rea ction.CoachMe. Addition of HBr to alkenes in presence of peroxide. They have planar to pyramidal geometry depending upon the groups attached to the C-atom having odd electron.co.in . Alkyl free radicals are stabilised by hyperconjugation whereas allyl and benzyl free radicals are stabilised by resonance. They are formed as intermediates in the reaction mixture either in the gaseous phase or in nonpolar solvents. + Br2 CCl 4 Number of product (including stereo) formed in the reaction: (A) 1 (B) 2 (C) 3 (D) 4 167. a lkene behave a s a nucleophile or base. the substitution of allylic or benzylic hydrogen by ‘Cl’ at high temperature or by ‘Br’ in presence of NBS are examples of reactions involving free radical intermediates. According to Markownikoff’s rule addition of electrophile occurs on that carbon of alkene which have more number of ‘H’ atom. H3 C CH 3 + NBS (A) (C) H3 C hv Expected Product H3 C CH 3 Br H3 C CH 3 (B) Br H3 C CH 3 (D) Br Br CH 3 H3 C Br & CH 3 Br 169.5-dimethylcyclopentene reacts with N-bromosuccinimide (NBS) in CCl4 in presence of light or peroxide. . This reaction is also known as Markownikoff reaction. . . 3. . (A) (CH 3 )3 C > CH 2 =CH–CH 2 > CH 2 =CH > CH 3 . . CH 3 . X Ph–CH=CH 2 HX Ph–CH–CH 3 + Ph–CH2 –CH 2 –X Major Minor Organic Chemistry is easy by www. . . CH 2 =CH–CH2 . . Identify the product. . Arrange the following free radicals in the decreasing order of their stability. . . (D) CH 2 =CH–CH 2 > (CH3 )3 C > CH2 =CH > CH 3 Passage : 3 Addition of HX on alkene proceed through the formation of carbocation. (CH 3 )3 C. .Alkene & Alkyne 168.CoachMe.co. . . CH 2 =CH. (B) (CH 3 )3 C > CH 2 =CH–CH 2 > CH 3 > CH 2 =CH (C) CH 2 =CH–CH 2 > (CH3 )3 C > CH 3 > CH 2 = CH .in 55 . . . . in . THF (Tetrahydrofuran) is used to control reactivity of borane. Which of the following alkene can produce diastereomers ? (A) CH 3 –CH=CH–CH3 H (C) (B) CH 3 CH 3 CH=CH–CH3 (D) CH3 CH=CH2 171. CH 3CH=CH 2 BH 2.Alkene & Alkyne Mechanism : H H–X Ph H H –X C=CH 2 Ph H C–CH 3 + Ph–CH 2 –CH 2 H More stable Less stable H X Ph Ph C–CH 3 + X C H X + Ph C CH 3 H 3C Enantiomer H 170.CoachMe. 56 Organic Chemistry is easy by www. Regioselectivity of reaction in increased by using hindered boranes.THF H 2O 2 .co. OH CH 3 –CH 2 –CH 2 –OH Rea ction is regioselective. Which of the following alkenes will give Markownikoff reaction ? HCl (A) F3 C–CH=CH 2 HCl (B) H 3 C–CH=CH 2 HBr (C) O 2 N–CH=CH2 (D) CH 3 CH3 HBr C=CH 2 Passage : 4 Hydroboration oxidation reaction is a process of addition of H2O according to Markownikoff’s rule but product resemble Anti-Markownikoff of product. Predictions based on charge distributions:.e. The charge distribution is a scerta ined by the exa mina tion of the consequences of inductive and/or resona nce effect.co.in 57 . CH 3 D OH CH3 (A) (C) H H (B) H CH 3 OH D HOOC 173.This method assumes that the reactivities of different positions in a given molecule are determined only by their relative activation Organic Chemistry is easy by www. (ii).CoachMe. an electrophilic reagent will attack preferentially at the site of highest electron density and a nucleophilic reagent will attack preferentially at the site of lowest electron density. This approach is referred to as the isolated molecule method. Major product : H 2O 2 .OH COOH COOH COOH COOH H D H OD D H H D (A) H OD (B) H D (C) H OD (D) H OH COOH COOH COOH COOH Passage : 5 To predict relative reactivities of various positions in a given molecule two different methods are generally used.THF 172.Alkene & Alkyne BD 3.THF COOH D 2O 2 . Predictions based on stabilities of intermediates:. (i). i.This approa ch assumes that the reactivities of a position in a polar reaction is determined by the cha rge density at that position.OH (D) H C=C CH 3 D OH CH 3 OH OH H BD 3. the lower its energy). (A) CH2 =CH 2 (B) CH2 =CH–Cl (C) CH2 =CH–OCH3 (D) CH 2 =CH–NO 2 175. In which molecule most stable intermediate will be formed after protonation.e. 174.CoachMe.Alkene & Alkyne energies. (A) 58 (B) O O (C) Organic Chemistry is easy by www. In Which molecule attack of electrophile will be easy over alkene. Based on these methods solve question 174–175. carbanion and free radicals. the lower is the energy of TS and consequently the lower is the energy of activation leading to that intermediate.co. it is these that are chosen to represent the structure of transition states. This approach is referred to as the localisation energy method. The assumption is then made that the more stable the intermediate (i. For the reactions that are belived to involve intermediate carbocation. the stabilities of which are then examined in terms of inductive effect and/or resonance effect.in Cl (D) Cl . Since the activation energy depends on the structures of the transition state. in 59 . If a pure enantiomer of 5-bromo-2-hexene is treated with Br2–CCl4. HCl. Br2 CCl 4 CH 3 H 178. Identify number of chiral centers present in product obtained by following reaction. How many of the following reactions.Alkene & Alkyne Integer type Questions : 176. How many different products (excluding stereoisomer) can be obtained by following reaction. If a racemic mixture of 3-methyl-1-pentene is treated with HCl. CCl 4 179. how many different tribromides would be formed? 180. how ma ny different chloropenta ne (importa nt products only excluding stereo) would be formed? Organic Chemistry is easy by www.CoachMe. leads to the formation of diastereomers.co. (A) H3 C HCl H Ph (C) HBr C=CH2 CCl 4 H HBr CCl 4 (B) C=CH–CH 3 CCl 4 H (D) CH3 HCl D CCl 4 CH CH Ph CH 3 (E) CH 2 Ph HCl CCl 4 HCl CCl 4 (F) CH 3 177. CoachMe. Acid catalyzed hydration of alkenes except ethene leads to the formation of [AIEEE-2005] (A) Mixture of secondary and tertiary alcohols (B) Mixture of primary and secondary alcohols (C) Secondary or tertiary alcohol (D) Primary alcohol 60 Organic Chemistry is easy by www. Rea ction of one molecule of HBr with one molecule of 1.in .co.Alkene & Alkyne Exercise 03 World of competitions 1. [AIEEE-2005] (A) 1-Bromo-2-butene under kinetically controlled conditions (B) 3-Bromobutene under thermodynamically controlled conditions (C) 1-Bromo-2 -butene under thermodynamically controlled conditions (D) 3-Bromobutene under kinetically controlled conditions 3.3-butadiene at 40°C gives predominantly. What is the product when acetylene reacts with hypochlorous acid ? [AIEEE 2003] (A) CH 3 COCl (C) Cl 2 CHCHO (B) ClCH 2 CHO (D) ClCHCOOH 2. C 6 H5 – C C – CH 3 H2 SO 4 [IIT-JEE 2003] O (A) (C) (B) C 6 H5 – C=CHCH 3 OH (D) O C 6 H5 – CH=C–CH 3 OH Organic Chemistry is easy by www. (C) Assertion is True. Rea son is correct explanation for Assertion. Acid catalyzed hydration of alkenes except ethene leads to the formation of [AIEEE-2005] (A) Primary alcohol (B) Secondary or tertiary alcohol (C) Mixture of primary and secondary alcohols (D) Mixture of secondary and tertiary alcohols 6. (B) Assertion is True. Rea son is True. Reason is NOT a correct explanation for Assertion.Alkene & Alkyne 4. Reason is True.CoachMe. [IIT-JEE 2001] Reason: Bromine addition to an alkene is an electrophilic addition (A) Assertion is True. Reason is True. Reason is False. (D) Assertion is False. HgSO 4 A 7. Assertion: Addition of fbromine to tra ns-2-butene yields meso-2. HBr reacts with CH2 =CH–OCH3 under anhydrous conditions at room temperature to give [AIEEE-2006] (A) CH3 CHO and CH 3 Br (B) BrCH 2 CHO and CH 3 OH (C) BrCH 2 –CH2 –OCH 3 (D) H 3 C–CHBr–OCH3 5. 3-dibromobutane.in 61 .co. Alkene & Alkyne 8. On acid catalysed hydration, 2-phenyl propene gives: [JEE 2004] (A) 2-phenylpropan-2-ol (B) 2-phenylpropan-1-ol (C) 3-phenylpropan-2-ol (D) 1-phenylpropan-1-ol 9. A n organic compound (P), C 5H10O reacts with dil. H2SO4 to give (Q) and (R). Both (Q) and (R) give positive iodoform test. The reactivity of organic compound (P) is 1015 times more than ethylene with respect to dil. H2SO4. [IIT-JEE 2004] (i) Identify the compounds (P), (Q) and (R) (ii) Give reason for the extraordinary reactivity of compound 10. CH 3 –CH=CH 2 + NOCl P [IIT-JEE 2006] Identify the adduct (A) CH 3 –CH–CH 2 Cl NO (B) CH 3 –CH–CH 2 NO Cl NO CH 2 –CH2 –CH 2 (C) CH 3 –CH 2 –CH (D) NO Cl Cl 11. The number of stereoisomers obtained by bromination of trans-2-butene is [IIT-JEE 2007] (A) 1 (B) 2 (C) 3 (D) 4 12. The major product of the following reaction is [IIT-JEE 2011] RCH 2OH O H (anhydrous) (A) a hemiacetal (B) an acetal (C) an ether (D) an ester 13. In the hydroboration-oxida tion rea ction of propene with diborane, H2 O2 and NaOH, the organic compound formed is: [IIT-Mains 2014] (A) CH3 CH 2 OH (B) CH3 CHOHCH3 (C) CH 3 CH 2 CH 2 OH (D) (CH 3 )3 COH 62 Organic Chemistry is easy by www.CoachMe.co.in Alkene & Alkyne CH2 –CH 2 =CH 2 on mercura tion-demercura tion pro- 14. duces the major product: CH2 –CH–CH3 (A) OH CH2 –CH–CH2 (C) OH OH [IIT-Mains 2014] CH2 –CH 2 –CH2 –OH (B) CH 2 –COOH (D) 15. In the following reaction, the major product is CH3 [IIT-Adv. 2015] CH 2 1 equivalent HBr CH3 (A) H2 C CH 3 CH 3 (B) Br H3 C Br CH3 (C) CH3 H2 C (D) Br H3 C Br Comprehension: In the following reactions C 8 H6 [IIT-Adv. 2015] i. B H Pd-BaSO 4 H2 C8 H 8 ii. H2 O6 , NaOH , H O X 2 2 2 H 2O HgSO 4 , H 2SO 4 C 8 H8 O i. EtMgBr, H 2O ii. H + , heat Y 16. Compound X is: O (A) (C) OH CH 3 OH (B) CH 3 (D) CHO Organic Chemistry is easy by www.CoachMe.co.in 63 Alkene & Alkyne 17. The major compound Y is: CH 3 (A) CH2 (C) CH 3 (B) CH 3 CH 3 (D) CH 3 18. Anti-Markownikoff addition of HBr is not observed in : [CET (J & K) 2012] (A) 2-butene (B) 1-butene (C) propene (D) 2-pentene 19. The negative part of the addendum adds on to unsaturated carbon atom joined to the least number of hydrogen atoms. This statement is called: [AFMC 2004] (A) Saytzelff rule (B) Kharasch effect (C) Markownikoff’s rule (D) Anti-Saytzeff rule 20. When propyne is treated with aqueous H2SO4 in presence of HgSO4, the major product is: [PMT (Kerala) 2010] (A) propanone (B) 2-propanol (C) ethanal (D) ethyne 21. Reaction of HBr with propene in the presence of peroxide gives: [AIPMT 2004] (A) isopropyl bromide (B) allyl bromide (C) n-propyl bromide (D) 3-bromopropane 22. Which of the following rea ctions will yield 2 ,2 dibromopropane? [CPMT 2004] (A) H2C = CHBr + HBr (B) CH3C = CCH3 + 2HBr (C) CH3C = CH + 2HBr (D) CH3CH = CHBr + HBr 23. Which of the following alkenes will give an optically active alcohol when treated with H2O/H2SO4? [CPMT 2004] (A) 1-Butene (B) Ethene (C) Propene (D) 2-Methyl propene 64 Organic Chemistry is easy by www.CoachMe.co.in Trans-2-butene-Br2 gives: [CET (Gujarat) 2006] H (A) H CH 3 Br Br CH 3 Br (B) H CH 3 H Br CH 3 Br (C) H CH3 Br H CH 3 H (D) Br CH 3 Br H CH3 28. Reaction of acetylene and propylene with HgSO4 in presence of HgSO4 produces respectively: [BHU (Med.) 2006] (A) acetone and acetaldehyde (B) acetaldehyde and acetone (C) propanaldehyde and acetone (D) acetone and propanaldehyde Organic Chemistry is easy by www.) 2008] (A) primary alcohol (B) secondary of tertiary alcohol (C) mixture of primary and secondary alcohols (D) mixture of secondary and tertiary alcohols 25. The only alcohol that can be prepared by the indirect hydration of alkene is: [AFMC 2005] (A) ethyl alcohol (B) propyl alcohol (C) isobutyl alcohol (D) methyl alcohol 26. 3-phenyl propene on reaction with HBr gives (as a ma jor product): [AIIMS 2005] (A) C 6 H 5 CH 2 CH(Br)CH3 (B) C 6 H 5 CHCH(Br)CH 2 CH3 (C) C 6 H 5 CH 2 CH 2 CH 2 Br (D) C 6 H 5 CH(Br)CH = CH2 27.Alkene & Alkyne 24.CoachMe. Acid catalysed hydration of alkenes except ethene leads to the formation of: [JCECE (Med.in 65 .co. CH 3 – CH – CH = CH 2 + HBr CH 3 (B) CH 3CH2 – C – CH 3 Cl I (D) CH 2 CH 2 CH 2 – C – H Cl 'A' . The order of reactivity of the alkenes.CoachMe. Hg 2 + [DUMET 2010] ? (A) PhCH2 CH 2 CHO (B) PhCOCH2 CH3 (C) PhCH 2 COCH3 (D) PhCOCOMe 66 Organic Chemistry is easy by www. II H 2 C = CH 2 III when subjected to acid catalyzed hydration is: [AMU (Med.Alkene & Alkyne 29.) 2009. (CH 3 )2 C = CH 2 . Predict the product ‘C’ obtained in the following reaction of 1butyne: HI CH3 CH 2 C CH + HCl (B) (C) [AIPMT 2007] I I (A) CH 3 CH2 – CH – CH2 Cl (C) CH 3 – CH – CH2 CH2 I Cl 30. I CH3 CH = CH2 . 10] (A) I > II > III (B) I > III > II (C) III > II > I (D) II > I > III 32. Identify the product in the reaction Ph–C C–Me H 3O+ .in . ‘A’ (predominantly) is: [AIPMT 2008] (A) CH 3 – CH – CH – CH 3 Br CH 3 (B) CH 3 – CH – CH – CH 3 CH 3 Br Br (C) CH 3 – CH – CH 2 – CH2 Br (D) CH 3 – C – CH 2 CH 3 CH 3 CH 3 31.co. The possible alkene is : [AIPMT 2015] CH 2 (A) CH3 (B) (A) (B) CH 3 (C) (A) and (B) (D) Organic Chemistry is easy by www. In the reaction with HCl. to give a product 1-chloro-1methylcyclohexane.CoachMe.Alkene & Alkyne 33. In the following reaction CH 3 CH 3 – C – CH = CH 2 C2H 5 H 2O / H + (A) major product The major product is : + (B) minor product [AIPMT (Prelims) 2012] CH 3 (A) H3 C – C – CH – CH 3 CH 3 OH (B) H3 C – C – CH – CH 3 OH CH3 CH 3 (C) CH 2 – C – CH 2 CH 3 OH CH 3 CH 3 (D) H3 C – C – CH 2 – CH 2 OH CH 3 CH 3 35. Reaction of HBr with propene in absence of peroxide is a/an: [PMT (Kerala) 2011] (A) electrophilic addition (B) electrophilic substitution (C) nucleophilic addition (D) nucleophilic substitution 34.in 67 . an alkene reacts in accordance with the Markovnikov’s rule.co. CoachMe. Organic rea ctions are generally of 4 types. e– deficient or odd e– species. 68 Organic Chemistry is easy by www. A – B – C A – C – B 2. Rea gents are the a ttacking species which attacks over the substrate. A= B +C –D π A– B σ σ C D (C) Elimination reaction– Here generally old bonds are broken & corresponding a new bonds are formed. A – B C A – C B (B) Addition reaction– Here generally bonds are broken & corresponding bonds are formed.Alkene & Alkyne Answers 01 Subjective Approach 1. (A) Substitution reaction– Here old sigma bonds are broken & new bond is formed.in . A –B σ C σ A= B+C– D π D (D) Rearrangement reaction– Here generally there is change in connectivity of atom. They may be e– rich.co. Leaving groups are those atoms or groups which goes out from substrate from any chemical reaction. They have complete octet with either presence of lone pair or –ve charge. Those factors which stabilizes leaving group increa ses its leaving group tendency. They have e– deficiency in the form of either (A) Positive charge (B) Incomplete octet or (D) Vacant orbital Those factors which withdraws e– density from electrophile increases its electrophilicity. 4. Electrophiles are e deficient attacking species. peroxide or high temperature.Alkene & Alkyne – 3. O 7. 5.in 69 . Free ra dicals are generally formed by either presence of light. O CH 3 –S–O – > CH3 –C–O – > Ph–O – > H–O – O I – > Br– > Cl – > F – H 2 O NH 3 9. – – O – OH > Ph–O > CH 3 –C–O > CH 3 –S–O – O I – > Br– > Cl – > F – NH 3 H 2 O O 8. Free radicals are odd e– reactive species which attacks over another free radicals or neutra l molecules. Solvents a re the medium in which chemical reaction has to take place.CoachMe. 6. They are of 2 types (A) Polar (B) Non polar Organic Chemistry is easy by www. Nucleophiles are e– rich attacking species which a ttacks are non-metal.co. Those factors which donates e– density towa rds nucle ophilic centre genera lly increa ses its nucleophilicity. NH3 . This rule is called as Markownikoff rule. Ba se a re those e – rich species which a tta cks over H + . When unsymmetrica l a lkene or a lkyne rea cts with unsymmetrical reagent in electrophilic addition reaction.CoachMe. Polar solvent are further of 2 types (A) Polar protic– where H+ can be removed from solvent such as H2 O. CH3 OH etc. 11. Basic concept behind Markownikoff rule is the sta bility of carbocation. CH3 SCH3 etc. Non polar solvent are those which do not have any pola rity in molecule such a s benzene. General chemical reaction of alkene & alkynes are electrophilic addition reaction.Alkene & Alkyne Polar solvents are those which have polarity in the molecule such as H2 O. E CH 3 – CH = CH2 E–Nu CH3 – CH – CH 2 Nu 12. 10.in . CH3 COOH (B) Polar aprotic– where solvent do not ea sily loose H+ but have polarity such as CH3 COCH3 . E CH 3 – CH = CH2 E–Nu CH3 – CH – CH 2 Nu 13. HCl CCl 3 – CH = CH2 CCl 3 – CH 2 – CH 2 – Cl (Violation of Markownikoff rule) Cl | HCl CH3 – CH = CH 2 CH 3 – CH– CH 3 (Follow Markownikoff rule) 70 Organic Chemistry is easy by www. then positive part of reagent attached to that carbon which have more number of hydrogen while negative part of reagent attached to that carbon which have less number of hydrogen.co. Nucleophile are those e– rich species which attacks over nonmainly C. cyclohexane. Ligand are those e– rich species which attacks over metal. . (B) Hydrobora tion-oxida tion using B 2 H6 followed by H 2 O2 /OH – . CH3 – CH – CH 3 H 2O H+ OH CH3 – CH – CH 3 17. (A) Hydration in acidic medium using H 2 O /H + . OH | i) Hg (OAC)2 /H2O CH3 – CH = CH 2 CH3 – CH– CH3 ii) NaBH 4 19. Alkoxymercura tion-demercuration is addition of a lcohol using (Ac2 O)2 Hg / ROH followed by NaBH 4 . Addition of water to alkene is hydration reaction. 16. 15. (A) Bromine water test (B) Baeyer’s reagent. (C) Oximercuration-demercuration using (Ac2 O)2 Hg / H 2 O followed by NaBH 4 . 18.in 71 .CoachMe. Reaction: H2 O/H+ OH | CH 3 . It is used to distinguish sa tura tion & unsa tura tion of carbon-carbon bond. Oximercuration-demercuration is addition of water to alkene using (Ac2 O)2 Hg / H 2 O followed by NaBH 4 .co.CH 3 Mechanism: CH 3 – CH = CH2 H+ .Alkene & Alkyne 14.CH = CH2 CH 3 – CH. Dilute alkaline KMnO 4 is commonly called as Baeyer’s reagent. Hydration of a lkene ta kes pla ce in a cedic medium & rea ction & mechanism follow as below. OR i)(AC2 O)Hg/ROH | CH3 – CH = CH 2 CH 3 – CH– CH 3 ii) NaBH 4 Organic Chemistry is easy by www. i)B H ii) H2 O 2 /OH 2 6 CH3 – CH = CH 2 - CH 3 – CH 2 – CH 2 – OH 21. Hydroboration-oxidation is simply a ddition of wa ter but machanism follow via 4 membered cyclic TS. Bromination of alkene is simply the addition of bromine to alkene to form dibromoalkane as product. i) B H or BH 2 6 3 CH3 – CH = CH 2 – CH 3 – CH2 – CH 2 – OH ii) H2 O 2 /OH Mechanism: CH3 –CH= CH 2 H – BH2 CH 3– CH H CH 2 CH 3– CH 2 –CH 2 –BH2 BH 2 (CH 3 –CH 2 –CH 2 )3 B H O /OH– 2 2 (CH 3 – CH 2 – CH2 )3 B 3 CH 3 – CH2 – CH 2 – OH As here hydrogen attached as hydride so reaction follows Markownikoff rule but product resemble’s Anti Markownikoff product. 22. Reaction: Br Br2 | CH 3 – CH = CH2 CH 3 – CH– CH 2 | Br Mechanism: CH 3–CH= CH 2 Br Br 72 Br CH 3–CH CH 2 Br Br CH 3– CH–CH 2 (Cyclic bromonium ion) Organic Chemistry is easy by www.in Br .co. Hydroboration-oxidation is a ddition of water using B 2 H6 followed by H 2 O2 /OH – .CoachMe.Alkene & Alkyne 20. Alkene & Alkyne 23. Reaction: OH | HO–Cl CH3 – CH = CH 2 CH 3 – CH– CH 2 | Cl Mechanism: CH 3–CH=CH . Cl OH HO CH 3 – CH CH 2 CH 3 –CH–CH2 Cl Cl OH Organic Chemistry is easy by www.in 73 .CoachMe. Reaction: Br | HBr CH 3 – CH = CH2 CH 3 – CH– CH 3 Mechanism: Br CH 3 – CH = CH2 H CH3 – CH – CH 3 Br CH 3 – CH – CH 3 25. Br Br2 /CCl 4 CH 3 –CH–CH 2 Br Br CH 3 –CH=CH2 Br2 /H 2O CH 3 –CH–CH 2 + CH3 –CH–CH 2 Br Br Br2 /NaCl Cl Br CH 3 –CH–CH 2 + CH3 – CH – CH2 Br Br Br2 /CH 3OH OH OCH 3 Br CH 3 –CH–CH 2 + CH3 –CH–CH 2 Br Br 24.co.. in .co.. I Cl CH3–CH CH 2 CH 3– CH–CH2 I I Cl 27. Reaction: Cl | I–Cl CH3 – CH = CH 2 CH 3 – CH– CH 2 | I Mechanism: Cl CH 3–CH=CH 2 . HBr/(Ph C O)2 O 2 CH3 –CH=CH 2 CH 3 –CH2 –CH2 –Br 74 Organic Chemistry is easy by www.Alkene & Alkyne 26.CoachMe. Cl OH 8 I Cl 7 Br Cl 1 HCl ICl HOCl H2 O/H+ Br2 / H2O OH 6 Br2 /CCl4 OH 2 ii) (Ac2 O)Hg/H2O ii) NaBH4 i ) BH 3 ii) H 2O 2 /OH– Br Br 5 4 OH OH 3 28. This concept is a gainst Ma rkownikoff rule so it is ca lled a s Anti-Markownikoff rule. When unsymmetrical alkene is treated with HBr in presence of peroxide then hydrogen will attached to that carbon which have less number of hydrogen while bromine is attached to that carbon which have more number of hydrogen. This abnormality was first reported by kharasch so it is called as Kharasch effect. Br | NBS CH 3 – CH = CH2 CH 2 – CH = CH 2 30.in 75 . CH2 – CH = CH 2 CH 2 – CH = CH 2 High T 32. NBS is used to replace benzylic or allylic H with Br via free radical mechanism. Reaction: Cl | HCl CH3 – C CH CH 3 – C – CH 3 | Cl Mechanism: Cl CH 3–C CH HCl CH 3 –C=CH 2 Cl CH 3– C= CH 2 Cl CH 3 –C–CH 3 H Cl Cl CH3 – C–CH 3 Cl 34. (A) Br Br (B) Br (C) (D) Br 33.CoachMe. NCS is N-Chloro Succinimide.Alkene & Alkyne 29. NBS is N-Bromo Succinimide. Reaction: O CH 3 – C CH HOCl CH3 – C – CHCl 2 Organic Chemistry is easy by www.co. NCS is used to replace benzylic or allylic H with Cl via free radical mechanism. Cl NCS | CH3 – CH = CH 2 CH 2 – CH = CH2 Cl Cl 2 | 31. . CH 3 – C CH i) B2H 6 – ii) H 2O 2/OH CH 3 – CH2 – C – H 36.in O CH 3–C–CH 3 . OH CH 3 –C CH OH CH3 –C=CH . . CH 3–C CH H 2O/HgSO 4 /H + O CH3 – C – CH3 Mechanism: .Alkene & Alkyne Mechanism:.Cl CH 3 –C = CH Cl . Mercury sulpha te rea cts with a lkyne a nd form a n intermediate over which water attacks to form product.co. H 2O CH 3–C CH HgSO 4 CH 3–C=CH O–H CH 3–C=CH 2 Hg Intermediate 76 Organic Chemistry is easy by www.CoachMe.. H 2O CH 3 –C CH Hg 2+ O–H CH 3–C=CH –H + CH 3–C=CH2 O CH 3–C –CH3 Hg 37. General hydration of alkyne occur in presence of HgSO4 of along with dil H 2 SO 4 .Cl OH Cl OH HO OH O CH 3–C–CHCl 2 –H2 O CH 3–C–CHCl 2 OH CH 3 –C CH–Cl Cl OH O 35. Alkene & Alkyne Cl 38. CH 3–CH CH2 H+ CH 3–CH–CH 3 + CH 3–C CH H CH 3–C=CH 2 CH3 CH3 | 42. CH3 – CH – CH– CH 3 X CH3 – CH – CH2 – C – H Y CH3 | CH 3 – CH – C– CH 3 O Y Organic Chemistry is easy by www. HCl Cl 40. + CH 3–CH=CH 2 E CH3 –CH–CH 2 E (more stable) CH 3–C E+ CH CH 3–C=CH E (less stable) 41. Alkynes & water are electron rich so H+ is added to create electron deficient centre in alkene or alkyne over which water will attack.co.CoachMe. So alkenes are more reactive than alkynes.in 77 . Intermediates formed from alkene is generally more stable than intermediate formed from alkyne. HCl 39. CH3 – CH – CH2 – CH 2 – OH X CH 3 OH | O | | 43. As alkene. O 6 2 O O i) B 2H 6 ii) H 2O 2 /OH – + H 2O/H /Hg ICl H Cl 78 Br Cl Cl I I Cl 5 4 O Organic Chemistry is easy by www. Br M Br Br Br Br Br Br + Br Br O N Br Br Br OCH3 + Br Br Br OCH 3 O Br Br Cl Br + Br Br Br Cl P Br Br Cl Br 1 Cl 8 7 HCl O O2 H g/ )H BH 4 Br2 O a c2 A ii) N ( i) i) B 2H 6 ii) CH 3COOH O C l 45.in 3 2+ H .co.CoachMe.Alkene & Alkyne Br 44. 48.co.in 79 . Br 50.CoachMe. Br HBr + + Br 51. 49.Alkene & Alkyne 46. Rate of electrophilic addition reaction depends on stability of carbocation. Carbocation formed by 1. (A) Br + O + Br Br (C) O (B) Br O (D) N O Organic Chemistry is easy by www. (A) CH –C–CH 3 3 Br Br HBr 52. Rate of electrophilic addition reaction depends on the stability of carboca tion formed after protonation while stability of substrate depends on electronic delocalization of bond. Terminal alkyne have acidic hydrogen so give white ppt with Tollen’s rea gent & red ppt with Cu 2 Cl 2 /NH 4 OH but non-terminal alkyne do not give such reactions. + Br N (B) Br O 53.3 -Butadiene is more stable than carbocation formed by But-1-ene so is the order. Tollen's reagent R–C C Ag white ppt R–C CH Cu2 Cl 2 / NH 4OH R–C C Cu Red ppt Tollen's reagent No ppt R–C C–R Cu 2Cl 2 /NH 4OH No ppt 47. H 2O Ph–CH–C CH Ph–CH=C=CH –H+ O–H O Ph–CH=C=CH Ph–CH=CH–C–H 55.CoachMe..OH 54. (A) HO O (B) OH (C) O (D) Ph Ph 80 Organic Chemistry is easy by www.co.Alkene & Alkyne O (C) (D) O OH OH + H–C H .in . Ph–CH–C CH H + .. (D) 20. (A) 70. (C) 36. (A) 87. (A) 65. (B) 63. (C) 31. (B) 55. (D) 19. (D) 35. (A) 54. (B) 69. (A) 51.CoachMe. (B) 85. (A) 71. (A) 42. (B) 24. (A) 45. (D) 81. (A) 74. (D) 84. (C) 49. (C) 90. (C) 66.in 81 . (B) 18. (B) 26. (A) 86. (A) 06. (B) 04. (B) 21. (C) 44. (A) 76. (D) 41. (D) 58. (B) 77. (C) 09. (C) 82. (A) 78. (B) 59. (B) 57. (C) 83. (C) 72. (D) 32. (B) 60. (C) 46. (B) 03. (B) 43. (B) 02. (D) 30. (A) 40. (B) 33. (C) 13. (A) 05. (B) 34. (A) 73. (D) 67. (A) 14. (C) 27. (B) 11. (B) 23. (B) 50. (C) 89. (D) 79. (D) 15. (B) 56. (B) 48. (A) 68. (B) 07. (A) 80. (B) 29. (B) 17. (B) 12. (D) 75. (B) 37. (D) 53. (C) 25. (A) 08. (C) Organic Chemistry is easy by www. (C) 28. (A) 39. (A) 64. (D) 38. (A) 62.Alkene & Alkyne Answers 02 Objective Approach 01. (B) 47. (B) 52. (B) 61. (B) 88. (D) 22. (B) 16. (A) 10.co. B–P. D–Q.D) 131. B–Q. (A.C) 135.Q) 165.C. (C. (D) 116. B–R.D) 145.D) 150.B) 137.D) 123.CoachMe.Alkene & Alkyne 91. (C) 154.B. (A. (A) 160. (D) 172.C) 127. (A.B. C–S. (1) 179.B) 149.C) 122. (A–P. (B.C.C) 128. (A. (C) 175. (B. (A. (C) 170.D) 144.C.C) 139.B. (A–S.C) 141. C–P. (A) 169. (3) 178.B. (A–Q.B. D–T) 162.Q. (C.B. (4) 180.B) 147. (B. (A.C. (A) 155.C) 134. (A. (A) 153. (A) 117.D) 138. (C) 96. (B) 98. (C) 158. (B) 156. (B) 114. (A) 104.B. (A.C.D) 136. B–R. (A. (A) 152.(A.B.(A.C) 146.(A.D) 140.B. (B. (A.C) 148.C) 151.D) 129. (A.C. (B) 101. (C) 93.D) 132.D) 130. C–R. (B) 110.D) 142. (B) 97.co.B. (C) 92. (C) 108.B. (A) 103. C–P. (A) 121. (C) 106. D–S) 164. (B) 167. (D) 119. (C) 107. (A) 168.(A. (A) 159.D) 143. (4) 177. (C) 113. (D) 99. (A.in . (A. (C) 171. (2) 82 Organic Chemistry is easy by www.(A.D) 126.C. C–S. (A–R. (C) 174.R.C.Q. (A. (B) 105. (B) 173.S) 166. (B) 118. (B) 109. (A–P. B–P. (B) 157. (B) 176. (A) 95. (A) 112. (C) 102. (A.(B.(B. (C) 94. (A.C.C. (C) 111. D–P. (A) 120.D) 124.B. (D) 115. (B) 161. (C) 100.D) 125. D–Q) 163.C) 133. (B.B. O O OH Q H R 09. 07.CoachMe. (A) 28. (B) 25. (C) 20. (D) 05. (D) 10. (A) 34. 08. (C) 22. (A) 24.in 83 . (B) 29. (B) 35. (C) 14. (B) 30. 06. (A) 19. (C) 32. P (C) 15. (A) Organic Chemistry is easy by www. (A) 12. (C) (A) 03. (D) 16. (D) 18. (A) 11. (D) 31.co. (A) 21. (B) 33. (C) 17. (C) 23. (C) (B) 02.Alkene & Alkyne Answers 03 World of Competitions 01. (C) (A) 04. (B) 27. (B) 13. (A) 26.