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
a)
b)
c)
d)
II
III
I, II, III, IV
III, I, II, IV
II, IV, I, III
I, III, IV, II
49
IV
Chapter 5 Reactions of Alkenes
9. Arrange these carbocations in order of increasing stability (least to most). (Sec. 5.3)
II
I
a)
b)
c)
d)
III
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 OsO 4/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
I, II, III
I, II, IV
II, IV
III, IV
50
IV. H2/Pt
Chapter 5 Reactions of Alkenes
15. Which is the product of the reaction of 1-methylcyclohexene with H2O/H2SO4? (Sec. 5.3)
CH3
CH3
H
CH3
H
H
OH
OH
OH
CH3
H
OH
OH
a)
c)
b)
d)
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 Br 2/CCl4? (Sec. 5.3)
Br
H
H
Br
a)
Br
H
H
H
Br
Br
b)
c)
Br
Br
d)
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)
c)
51
d)
Chapter 5 Reactions of Alkenes
20. Which is the major product from the reaction of 1,2-dimethylcyclohexene with D2/Pt? (Sec. 5.5)
CH3
D
CH3
D
D
CH3
CH3
D
CH3
D
CH3
D
D
b)
a)
CH3
d)
c)
21. Which alkene has the highest rate of reaction with HBr? (Sec. 5.3)
c)
b)
a)
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
reaction coordinate
C
D
23. Which compound does not give two isomers when reacted with Cl 2/CCl4? (Sec. 5.3)
a)
b)
CH3
D
c)
52
d)
Chapter 5 Reactions of Alkenes
24. Which compound has the lowest (least negative) heat of hydrogenation? (Sec. 5.5)
b)
a)
c)
d)
25. Which point on the potential energy diagram represents the activation energy? (Sec. 5.2)
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
54
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
C
55
+
Cl
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)
56
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
58
Chapter 5 Reactions of Alkenes
5.
Br2
CH2Cl2
6.
H+
H2O
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
60