Chapter 7 Haloalkanes
Multiple Choice
1. Which of the following structures have the correct IUPAC name? (Sec. 7.2)
Cl
H
C CH CH CH
2
2
3
CH3
CH3
F
R-2-chloropentane
I
R-4-fluoro-4-methylcyclohexene
II
H3CO
Br
H
CH3
Cl
Br
H
S-2-chloro-2-fluorobutane
IV
I, II
III, IV
I, III
II, IV
2. Which of the following structures have correct common names? (Sec. 7.2)
H3C
H2C
CHCH2F
CHCH2Br
H3C
allyl fluoride
I
isobutyl bromide
II
I
HCCl3
methylene chloride
III
a)
b)
c)
d)
F
CH2CH3
OCH3
meso-1,2-dibromo-1,2-dimethoxyethane
III
a)
b)
c)
d)
C
H3C
CH CH2CH3
isopropyl iodide
IV
I, II
III, IV
I, III
II, IV
75
Chapter 7 Haloalkanes
3. Which of the following compounds are secondary halides? (Sec. 7.6)
I) Isobutyl bromide
a)
b)
c)
d)
II) 2-iodobutane
III) isopropyl fluoride
IV) neopentyl chloride
I, II
III, IV
II, III
I, IV
4. Which compounds are primary halides? (Sec. 7.6)
H
CH3
CH3
H3C C C
H3C C Cl
CH3
I
H3C CH2 CBr3
FH2C CH2 CH
CH3
I
a)
b)
c)
d)
CH3
CH3
II
III
IV
I, II
III, IV
II, III
I, IV
5. Which of the following halides is prepared from the following reactions? (Sec. 7.1, 5.3)
HBr
Br
Br
Br
Br
Br
a)
b)
c)
d)
6. Which is the best reaction condition for preparing 2-iodohexane from 1-hexene? (Sec. 7.1, 5.3)
a)
b)
c)
d)
I2 / CCl4
HI
NaI
HIO4
76
Chapter 7 Haloalkanes
7. Arrange the nucleophiles in order of increasing reactivity (least first). (Sec. 7.6)
NH3
H2O
OH
I
II
III
a)
b)
c)
d)
CH3O
IV
I, IV, II, III
IV, II, I, III
II, I, III, IV
IV, III, I, II
8. Arrange the nucleophiles in order of increasing reactivity (least first). (Sec. 7.6)
O
H3CCO
H3CO
Br
H2O
II
III
IV
I
a)
b)
c)
d)
III, II, I, IV
IV, I, II, III
I, III, II, IV
III, I, IV, II
9. Arrange the leaving groups in order of increasing leaving group ability (least first). (Sec. 7.6)
O
H3CCO
I
a)
b)
c)
d)
H3CO
Br
HO
II
III
IV
I, III, II, IV
III, I, IV, II
VI, II, I, III
IV, III, II, I
10. Arrange the leaving groups in order of increasing leaving group ability (least first). (Sec. 7.6)
a)
b)
c)
d)
Cl
I
Br
F
I
II
III
IV
IV, I, III, II
III, I, IV, II
II, IV, I, III
II, III, I, IV
77
Chapter 7 Haloalkanes
11. Arrange the alkyl halides in order of increasing reactivity in an S N2 reaction with KI in acetone (least first).
(Sec. 7.6-7.7)
Cl
CH2CH2Br
Cl
Br
CCH3
CH3
I
a)
b)
c)
d)
II
III
I, IV, III, II
IV, I, III, II
II, III, I, IV
III, II, IV, I
12. Which are optimum conditions for an SN2 reaction? (Sec. 7.6-7.7)
I.
II.
acetone
CH2Cl
+
NaSH
Cl
+
CH3OH
+
CH3S Na
+
NaI
CH3
III.
Cl
IV.
a)
b)
c)
d)
CH2Br
I, II
II, III
III, IV
I, IV
78
H 2O
DMSO
DMSO
IV
Chapter 7 Haloalkanes
13. Which nucleophilic substitution reactions will proceed? (Sec. 7.6-7.7)
I. NaCl + CH3CH2OH
II. NH3
+
acetone
Br
ethanol
III. CH3CH2O + CH3CH2CH2Cl ethanol
IV. LiCl + CH4
a)
b)
c)
d)
acetone
I, II
II, III
III, IV
I, IV
14. Which reactions will proceed with inversion of configuration? (Sec. 7.6-7.7)
OCH2CH3
R-2-bromohexane
CH3CH2OH
S-2-iodobutane
OH
R-3-bromo-3-methylhexane
CH3CH2OH
III.
R-2-bromohexane
I, II
III, IV
II, III
I, IV
I) DMSO
II) H2O
III) Acetone
IV) Formic acid
II, III
III, IV
I, III
II, IV
79
CH3OH
heat
IV.
15. Which solvents are polar aprotic? (Sec. 7.6)
a)
b)
c)
d)
acetone
II.
I.
a)
b)
c)
d)
NaSCH3
Chapter 7 Haloalkanes
16. Arrange the alkyl halides in order of increasing rate of solvolysis (slowest first)? (Sec. 7.6)
CH3
H3CH2C
H3C CCl
CHCl
H3CH2C
CH3
I
a)
b)
c)
d)
H3C
CHCl
III
II
IV, III, II, I
I, II, III, IV
III, II, I, IV
II, III, I, IV
17. Which conditions are optimum for an SN1 reaction? (Sec. 7.6-7.7)
a)
CH3CH2Cl
+
NaCN
CHCl
+
CH3OH
CH3CH2CH2Br
+
NaSH
+
NaCN
acetone
H3C
b)
H2O
H3C
c)
DMSO
CH3
d)
H3C CCl
DMSO
CH3
18. Which solvents are polar protic? (Sec. 7.6)
I) ethanol
II) hexane
III) DMSO
IV) water
a)
b)
c)
d)
CH3CH2CH2Cl
H3C
III, IV
II, III
I, IV
I, III
80
IV
Chapter 7 Haloalkanes
19. Which statements apply to an SN1 reaction? (Sec. 7.6)
I) The rate limiting step of the reaction involves the alkyl halide and the nucleophile.
II) The order of reactivity is methyl > 1°>2°>3°.
III) The rate limiting step of the reaction involves only the alkyl halide.
IV) There is an intermediate carbocation.
a)
b)
c)
d)
I, II
III, IV
I, IV
III
20. Which statements apply to an SN2 reaction? (Sec. 7.6)
I) The rate limiting step of the reaction involves the alkyl halide and the nucleophile.
II) The order of reactivity is methyl > 1°>2°>3°.
III) The rate limiting step of the reaction involves only the alkyl halide.
IV) There is an intermediate carbocation.
a)
b)
c)
d)
I, II
III, IV
I, IV
II, IV
21. Which conditions are optimum for an E2 reaction? (Sec. 7.8-7.9)
a)
CH3I
+
CH3
b) CH3CHCl
DMSO
F
CH3
+
CH3CO K
DMSO
CH3
CH3
c) CH3CHCH2Cl
+
CH3OH
+
CH3O
CH3
d) CH3CHCH2Br
H2O
H2O
22. What is the major product from an elimination reaction starting with 2-bromopentane? (Sec. 7.8-7.9)
a)
b)
c)
d)
1-pentene
cis-2-pentene
trans-2-pentene
a mixture of cis and trans-2-pentene
81
Chapter 7 Haloalkanes
23. Which alkyl halide leads to the product shown, in an E2 reaction? (Sec. 7.8-7.9)
CH2
Cl
CH2Cl
CH3
CH3
a)
b)
CH3
c)
d)
Cl
Cl
24. Which statements are true for an E1 reaction? (Sec. 7.9)
I) The rate limiting step of the reaction involves only the alkyl halide.
II) The rate limiting step of the reaction involves the alkyl halide and the base.
III) There is an intermediate carbocation.
IV) The order of reactivity is 1°>2°>3°.
a)
b)
c)
d)
I, III
II
I, III, IV
II, IV
25. Which conditions are best for preparing isopropyl methyl ether? (Sec. 7.10)
H3C
a)
Na OCH3
+
CHBr
H3C
CH3
b)
Na OCH
CH3
c)
+
CH3Br
H3C
CH3OH
+
CHBr
heat
CHOH
acid
catalysis
H3C
d)
H3C
CH3OH
+
H3C
82
Chapter 7 Haloalkanes
Fill in the Blank
1. The major product of the following reaction is,
KSCH3
Cl
H
DMSO
(Sec. 7.6)
2. The major product of the following reaction is,
KOH
Br
H2O
H
(Sec. 7.6)
3. The major product of the following reaction is,
NH3
H
I
(Sec. 7.6)
4. The major product of the following reaction is,
I
NaOCH2CH3
CH3CH2OH
(Sec. 7.9)
5. The major product of the following reaction is,
H2O
H Br
(Sec. 7.6)
6. The reagent needed to complete the following reaction is,
Cl
(Sec. 7.9)
83
Chapter 7 Haloalkanes
7. The reagent needed to complete the following reaction is,
H
Br
H
OH
(racemic)
(Sec. 7.6)
8. The reagent needed to complete the following reaction is,
Br
H
H3CO
H
H
OCH3
+
(Sec. 7.6)
9. The starting material needed to complete the following reaction is,
KI
I
CH3CH2OH
(Sec. 7.6)
10. The starting material needed to complete the following reaction is,
HS
H
NaSH
acetone
(Sec. 7.6)
True-False
1. Polar aprotic solvents favor SN1 reactions. (Sec. 7.6)
2. The order of SN1 reactivity of the following alkyl halides are listed in decreasing order. (Sec. 7.6)
Cl > H3C Cl
>
Cl
>
Cl
3. The order of SN2 reactivity of the following alkyl halides are listed in decreasing order. (Sec. 7.6)
Br >
I
>
F >
Cl
84
Chapter 7 Haloalkanes
4. The following nucleophiles are listed in decreasing order of reactivity in an SN2 reaction. (Sec. 7.6)
I- > Br- > Cl-
> F-
5. The following nucleophiles are listed in decreasing order of reactivity in an S N2 reaction. (Sec. 7.6)
F- > HO- > H2N6. The name of the following compound is cis- (1R,2S)-1-chloro-2-bromocyclohexane. (Sec. 7.2)
Cl
Br
7. The name of the following compound is R, E - 4-bromo-2-pentene. (Sec. 7.2)
Br
8. The major product of the reaction of R-2-bromobutane with sodium iodide in acetone is S-2-iodobutane.
(Sec. 7.6)
9. The major product of the reaction of R-2-bromobutane with water is a racemic alcohol. (Sec. 7.6)
10. The major product of the reaction of bromocyclohexane and potassium t-butoxide in water is an ether.
(Sec. 7.6)
85
Chapter 7 Haloalkanes
Answers
Multiple Choice
1. c
2. a
3. c
4. b
5. a
6. b
7. c
8. b
9. c
10. a
11. d
12. d
13. b
14. a
15. c
16. a
17. b
18. c
19. b
20. a
21. b
22. c
23. c
24. a
25. b
Fill in the Blank
1.
H SCH3
2.
H OH
3.
H2N
H
86
Chapter 7 Haloalkanes
4.
5.
+
HO H
H OH
6. base
7. H2O
8. HOCH3
9.
Br or
Cl
10.
H
Cl
(or –Br, -I)
True-False
1. F
2. F
3. F
4. T
5. F
6. F
7. T
8. T
9. T
10. F
87