Chapter 4 Alkenes and Alkynes
Multiple Choice
1. Which are the approximate carbon-carbon bond angles at positions I and II in the following compound?
(Sec. 4.2)
CH3
I
II
a)
b)
c)
d)
109°, 109°
120°, 180°
120°, 109°
109°, 120°
2. Which is the best description for the indicated bond in the following compound? (Sec. 4.2)
CH3
a)
b)
c)
d)
sp3-sp3
sp3-sp3 and 2p-2p
sp2-sp2 and
-2p
sp-sp and sp-sp
3. Which is the IUPAC name for the following structure? (Sec. 4.3)
CH3
H3C C CH CH2
CH2 CH3
a)
b)
c)
d)
3,3-dimethyl-4-pentene
3-methyl-3-ethyl-1-butene
isopropylpentene
3,3-dimethyl-1-pentene
4. Which is the correct structure for vinylcyclobutane? (Sec. 4.3)
CH2
a)
b)
CH2
c)
CH CH2
d)
36
Chapter 4 Alkenes and Alkynes
5. Which is the correct name for the following compound? (Sec. 4.3)
CH3
H3C
C
H
C
C
C
CH2
H
a)
b)
c)
d)
CH3
H
2E, 5E-5-methyl-2,5-heptadiene
2E, 5E-3-methyl-2,5-heptadiene
2Z, 5E-3-methyl-2,5-heptadiene
2E, 5Z-5-methyl-2,5-heptadiene
6. Which is the correct name for the following compound? (Sec. 4.3)
CH3
CH3
a)
b)
c)
d)
1,3-dimethylcyclohexene
2,4-dimethylcyclohexene
3,5-dimethylcyclohexene
2,4-dimethyl-1-cyclohexene
7. Which is the correct name for the following compound? (Sec. 4.3)
H3C
CH3
C C
H
a)
b)
c)
d)
CH2CH3
E-2-ethyl-2-butene
Z-3-methyl-3-pentene
E-3-methyl-2-pentene
Z-3-ethyl-2-butene
8. Which is the IUPAC name for the following compound? (Sec. 4.3)
H3C C C CH3
a)
b)
c)
d)
dimethyl acetylene
3-butyne
3-butene
2-butyne
37
Chapter 4 Alkenes and Alkynes
9. Which is the IUPAC name for the following compound? (Sec. 4.3)
H3C
H3C
CH2CH3
a)
b)
c)
d)
1,1-dimethyl-4-ethyl-2,5-cyclohexadiene
1-ethyl-4,4-dimethyl-2,5-cyclohexadiene
3-ethyl-6,6-dimethyl-1,4-cyclohexadiene
6-ethyl-3,3-dimethyl-1,4-cyclohexadiene
10. Which of the following alkenes do not show cis-trans isomerization? (Sec. 4.3)
I) 2-methyl-2-hexene
II) 1-chloro-1-butene
III) 1-methylcyclohexene
IV) 2-methyl-3-hexene
a)
b)
c)
d)
I, II
III, IV
II, III, IV
I, III
11. Which of the following alkenes show cis-trans isomerization? (Sec. 4.3)
I) 1-chloropropene
II) 3-methylcyclohexene
III) 2,6-dimethyl-2,5-octadiene
IV) 3-ethyl-3-methyl-1-pentene
a)
b)
c)
d)
I, II
II, III
III, IV
I, III
12. How many trans isomers are there for an alkene with the formula, C4H7Cl? (Sec. 4.3)
a)
b)
c)
d)
2
3
6
8
13. How many cycloalkanes of molecular formula C5H10 show cis-trans isomerism? (Sec. 4.3)
a)
b)
c)
d)
1
2
3
4
38
Chapter 4 Alkenes and Alkynes
14. How many cycloalkanes of molecular formula C6H12 do not show cis-trans isomerization? (Sec. 4.3)
a)
b)
c)
d)
2
3
4
5
15. Arrange the following groups in the order of increasing priority (lowest first). (Sec. 4.3)
CH2CH3
CH2NH2
I
a)
b)
c)
d)
CH2Br
II
CH2OH
III
IV
I, II, IV, III
III, IV, II, I
I, IV, II, III
IV, II, III, I
16. Arrange the following groups in the order of increasing priority (lowest first). (Sec. 4.3)
CH CH2
C CH
II
I
a)
b)
c)
d)
C N
C O
CH3
IV
III
IV, III, II, I
I, II, III, IV
III, IV, I, II
III, I, IV, II
17. Arrange the following groups in the order of increasing priority (lowest first). (Sec. 4.3)
O
O
O
O
C OCH3
C OH
C CH3
C NH2
I
II
III
IV
a)
b)
c)
d)
II, I, IV, III
II, III, I, IV
I, II, IV, III
III, IV, II, I
39
Chapter 4 Alkenes and Alkynes
18. Which structure is Z-2-bromo-3-methyl-2-pentene? (Sec. 4.3)
CH3
H3C
CH2CH3
H
C C
Br
CH CH2CH3
H3C
C C
CH3
H
H3C
C C
Br
a)
CH3
Br
C C
CH2CH3
b)
Br
H3C
CH2CH3
c)
d)
19. Which alkenes have E configurations? (Sec. 4.3)
O
O
HO C
Cl
Cl
C OH
C C
H
H2C
C C
H
H
I
a)
b)
c)
d)
CH2Cl
F
Br
C C
CH3
H3C
II
Cl
III
Cl
C C
H3C
I
IV
I, II
II, III
III, IV
II, IV
20. How many cis-trans isomers are possible for geraniol? (Sec. 4.3 and 4.5)
CH3
H2C
H2C
C
C
H
CH2OH
CH
C
H3C
a)
b)
c)
d)
CH3
2
3
4
6
21. How many distinct terpene structure types can be made from the assembly of 2-isoprene units? (Sec. 4.5)
a)
b)
c)
d)
1
2
3
4
40
Chapter 4 Alkenes and Alkynes
22. How many isoprene units are there in vitamin A? (Sec. 4.5)
CH2OH
a)
b)
c)
d)
2
3
4
8
23. Cleavage of which of the indicated bonds in limonene leads to a head to tail terpene? (Sec. 4.5)
c)
d)
b)
a)
24. Arrange the following compounds in decreasing order of boiling point (highest first). (Sec. 4.4)
H3C C C CH2CH2CH3
I
a)
b)
c)
d)
CH3
H3C C C CH
CH3
II
CH3
H3C C C CH3
III
HC C C CH3
IV
I, II, IV, III
II, IV, III, I
III, IV, II, I
IV, II, III, I
25. Arrange the following molecules in order of increasing boiling point (lowest first). (Sec. 4.4)
I
a)
b)
c)
d)
II
III
I, II, IV, III
IV, II, III, I
III, IV, II, I
I, II, III, IV
41
IV
CH3
Chapter 4 Alkenes and Alkynes
Fill in the Blank
1. The IUPAC name of the following molecule is ____________________________________________________.
(Sec. 4.3)
2. The IUPAC name of the following molecule is ____________________________________________________.
(Sec. 4.3)
3. The structure of (3E, 6Z) 2,9-dimethyl-3,6-decadiene is
(Sec. 4.3)
4. The structure of 3,7-diethyl-4,8-dimethyl-1,5-cyclooctadiene is
(Sec. 4.3)
5. The IUPAC name of the following molecule is ____________________________________________________.
(Sec. 4.3)
42
Chapter 4 Alkenes and Alkynes
6. The structure of 2-cyclobutyl-6,6-dimethyl-4-octyne is
(Sec. 4.3)
7. The approximate bond angles of the indicated carbons are 1) ______, 2) _______, 3) _______, 4) ______.
(Sec. 4.2)
1
2
3
4
8. The number of isoprene units in menthol is ___________. (Sec. 4.5)
OH
9. The number of isoprene units in grandisol is ____________. (Sec. 4.5)
OH
H
10. The priority order of the groups –CH2CH3, -CH3, -OCH3, -CH=CH2 is;
>
>
>
(Sec. 4.3)
43
Chapter 4 Alkenes and Alkynes
True-False
1. The structure of 4-isopropyl-1-methylcyclohexene is
(Sec. 4.3)
2. The name of the following structure is (3E, 5E) 2-ethyl-3,5-octadiene. (Sec. 4.3)
3. The following compounds are listed in order of increasing boiling point (lowest first). (Sec. 4.4)
<
<
<
4. The following groups are listed in order of decreasing priority (highest first). (Sec. 4.3)
CH3
C CH >
CH
>
CH3
C CH2 >
H
CH3
5. The following groups are listed in order of increasing priority (lowest first). (Sec. 4.3)
O
O
H
<
Cl
<
OCH2CH3
<
Cl
6. The following structures represent identical compounds. (Sec. 4.3)
7. The following structures represent isomers. (Sec. 4.3)
8. 2,2-Dimethylcyclohexene occurs as E and Z isomers. (Sec. 4.3)
44
Chapter 4 Alkenes and Alkynes
9. 2,3-dimethyl-3-hexene occurs as E and Z isomers. (Sec. 4.3)
10. There are 4 possible E,Z isomers of 1,3-pentadiene. (Sec. 4.3)
45
Chapter 4 Alkenes and Alkynes
Answers
Multiple Choice
1. c
2. c
3. d
4. d
5. b
6. c
7. c
8. d
9. d
10. d
11. d
12. b, two alkenes and a cycloalkane
13. a
14. d
15. a
16. b
17. d
18. c
19. c
20. a
21. c
22. c
23. a
24. a
25. c
Fill in the Blank
1. (Z) 7-methyl-3-nonene
2. 6,6-dimethyl-1,4-cycloheptadiene
3.
4.
5. 2,8,9-trimethyl-3-decyne
46
Chapter 4 Alkenes and Alkynes
6.
7. 1) 120, 2) 109, 3) 120, 4) 180
8. 2
9. 2
10.
OCH3
>
C CH2 >
H
CH2CH3 >
True-False
1. F
2. F
3. F
4. F
5. T
6. T
7. F
8. F
9. T
10. F
47
CH3