Organic Chemistry Chapter 5 PDF

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Chapter 5 Reactions of Alkenes

Multiple Choice 1. The reaction of propene with which of the following reagents are oxidation reactions? (Sec. 5.3 - 5.5) HBr/CH2Cl2 I a) b) c) d)

OsO4 II

H2/Pt III

H+/H2O V

Br2 IV

II III I and V II and IV

2. Which point on the potential energy diagram represents the intermediate? (Sec. 5.2)

B C E

D A

reaction coordinate 3. Which diagram represents the slowest reaction? (Sec. 5.2)

E

E

reaction coordinate A

reaction coordinate B

E

E

reaction coordinate C

reaction coordinate D

48

Chapter 5 Reactions of Alkenes

4. Which compound has the highest heat (most negative) of hydrogenation? (Sec. 5.5)

A

C

B

D

5. Which statement does not describe a transition state? (Sec. 5.2) a) b) c) d)

Possesses a definite geometry Maximum on the potential energy diagram Structure can be determined experimentally Can not be isolated

6. Using Markovnikov’s rule, predict the position of the Cl atom in the major product from the reaction of 1methylcyclohexene with HCl. (Sec. 5.3)

A

C

B

D

7. Which species are electrophiles? (Sec. 5.3)

I a) b) c) d)

OH

NH3

H

II

III

IV

II, III II, IV I, IV I, III

8. Arrange these carbocations in order of increasing stability (least to most). (Sec. 5.3)

H3C I

II

III

IV

a) I, II, III, IV b) III, I, II, IV c) II, IV, I, III d) I, III, IV, II 9. Arrange these carbocations in order of increasing stability (least to most). (Sec. 5.3)

49

Chapter 5 Reactions of Alkenes

a) b) c) d)

I, II, III I, III, II II, I, III III, II, I

10. Which reagents react with an alkene by syn addition? (Sec. 5.3 - 5.5) I. Cl2 a) b) c) d)

II. Br2

III. H2/Pt

IV. OsO4/ROOH

I, II III, IV II, III I, IV

11. Which reagents react with an alkene by anti addition? (Sec. 5.3 - 5.5) I. Cl2 II. Br2 III. H2/Pt IV. OsO4/ROOH a) b) c) d)

I, II III, IV II, III I, IV

12. Which reagents react with an alkene in a Markovnikov orientation? (Sec. 5.3) I. HBr II. H2O/H2SO4 III. Br2 IV. OsO4/ROOH a) b) c) d)

I, II III, IV II, IV II, III, IV

13. Which is the major product from the reaction of propene with OsO4/ROOH? (Sec. 5.4) a) b) c) d)

1-propanol 2-propanol 1,2-propanediol 1,3-propandiol

14. Which reagents react with an alkene by an electrophilic mechanism? (Sec. 5.3) I. H2O/H2SO4 a) b) c) d)

II. Br2/CCl4

III. HBr

IV. H2/Pt

I, II, III I, II, IV II, IV III, IV

15. Which is the product of the reaction of 1-methylcyclohexene with H2O/H2SO4? (Sec. 5.3)

CH3

CH3

H

H

OH OH a)

H

CH3

OH

CH3

H OH

OH b)

50

c)

d)

Chapter 5 Reactions of Alkenes

16. Which is the major product from acid catalyzed hydration of 2-methyl-2-pentene? (Sec. 5.3) a) b) c) d)

2-methyl-3-pentanol 2-methyl-2-pentanol 4-methyl-2-pentanol 3-methyl-3-pentanol

17. Which is the intermediate formed in the reaction of propene with HBr? (Sec. 5.3)

Br Br a)

c)

b)

d)

18. Which is the major product from the reaction of cyclopentene with Br2/CCl4? (Sec. 5.3)

Br

Br

H

H

Br a)

H

H

H

Br

Br

b)

Br Br d)

c)

19. Compound A has a molecular formula C8H14 and reacts with H2/Pt to give compound B, C8H16. Which is compound A? (Sec. 5.5)

a)

b)

d)

c)

20. Which is the major product from the reaction of 1,2-dimethylcyclohexene with D 2/Pt? (Sec. 5.5) CH3

D

CH3

D D D CH3

a)

CH3 CH3

D CH3

CH3 D

D

D

b)

c)

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CH3

d)

Chapter 5 Reactions of Alkenes

21. Which alkene has the highest rate of reaction with HBr? (Sec. 5.3)

a)

c)

b)

d)

22. Which potential energy diagram represents the reaction of HBr with 2-butene? (Sec. 5.2)

E

E

reaction coordinate A

reaction coordinate B

E

E

reaction coordinate C

reaction coordinate D

23. Which compound does not give two isomers when reacted with Cl2/CCl4? (Sec. 5.3)

a)

b)

c)

d)

24. Which compound has the lowest (least negative) heat of hydrogenation? (Sec. 5.5)

a)

b)

c)

d)

25. Which point on the potential energy diagram represents the activation energy? (Sec. 5.2)

52

Chapter 5 Reactions of Alkenes

B C E

D A

reaction coordinate

53

Chapter 5 Reactions of Alkenes

Fill in the Blank 1. The stereoselective reagents from the following list are _________________________________. (Sec. 5.3-5.5) H+/H2O

HCl

Br2

OsO4

H2

2. Complete the following reaction by providing the major product. (Sec. 5.4)

OsO4 CH3COOH 3. Complete the following reaction by providing the major product. (Sec. 5.3)

HBr CH2Cl2

4. Complete the following reaction by providing the major product. (Sec. 5.5)

H2 Pt

5. Complete the following reaction by providing the necessary reagents. (Sec. 5.3)

Br Br

6. Complete the following reaction by providing the necessary reagents. (Sec. 5.3)

OH

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Chapter 5 Reactions of Alkenes

7. Complete the following reaction by providing the starting material and reagents. (Sec. 5.3)

Cl

Cl

8. Complete the following reaction by providing the starting materials. (Sec. 5.5)

H2 or Pt 9. Draw the intermediate of the following reaction. (Sec. 5.3)

+ HCl

10. Draw the intermediate of the following reaction. (Sec. 5.3)

+ Br2

11. Draw the reaction arrows (curved arrows) for the following reaction. (Sec. 5.3)

H

Cl +

H Cl

Cl

C

55

+

Chapter 5 Reactions of Alkenes

True-False

E C B D A E

reaction coordinate 1. The reaction represented by the above reaction energy diagram is endothermic. (Sec. 5.2) 2. The rate determining step of the reaction represented by the above reaction energy diagram is the first step. (Sec. 5.2) 3. The activation energies of the reaction represented by the above reaction energy diagram are noted as A and B. (Sec. 5.2) 4. The following carbocations are listed in increasing order of stability (least first). (Sec. 5.3)

H C

+

H

CH3 < HC 3

C

+

C

+

CH3

<

H

5. The following alkenes are listed in decreasing order of heat of hydrogenation (highest first). (Sec. 5.5)

>

>

>

6. The product of the reaction of cyclohexene and bromine is cis-1,2-dibromocycloheane. (Sec. 5.3) 7. The major product of the reaction of catalytic hydrogenation of 1,2-dimethylcyclohexene is cis-1,2dimethylcyclohexane. (Sec. 5.5)

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Chapter 5 Reactions of Alkenes

8. Bromination, catalytic hydrogenation, and hydroxylation via osmium tetroxide are cis stereoselective reactions. (Sec. 5.3-5.5) 9. Hydrohalogenation, hydration, and bromination reactions proceed through an open carbocation intermediate. (Sec. 5.3) 10. The reaction arrows (curved arrows) are accurately drawn for the following reaction. (Sec. 5.3)

H

H

Br

H Br

+

Br-

57

Chapter 5 Reactions of Alkenes

Answers Multiple Choice 1. d 2. c 3. a 4. b 5. c 6. c 7. c 8. b 9. d 10. b 11. a 12. a 13. c 14. a 15. b 16. b 17. d 18. a 19. a 20. b 21. d 22. c 23. a 24. d 25. d Fill in the Blank 1. Br2, OsO4, H2 2.

OH OH 3.

Br

4.

H

H

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Chapter 5 Reactions of Alkenes

5.

Br2 CH2Cl2

6.

H+ H 2O 7.

Cl2 CH2Cl2 8.

or 9.

+ 10.

Br

+

11.

H

Cl +

H Cl

C

59

+

Cl

Chapter 5 Reactions of Alkenes

True-False 1. F 2. F 3. T 4. F 5. F 6. F 7. T 8. F 9. F 10. F

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