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Alcohols, Phenols, Ethers, and Thiols
14
Answers and Solutions to Text Problems
14.1
In a primary (1°) alcohol the carbon bonded to the hydroxyl group (OH) is attached to one
alkyl group except for methanol; to two alkyl groups in a secondary alcohol (2°); and to three
alkyl groups in a tertiary alcohol (3°).
a. 1°
b. 1°
c. 3°
d. 2°
e. 3°
14.2
a. secondary
d. tertiary
14.3
a. This compound has a two-carbon chain (ethane). The final −e is dropped and −ol added to
indicate an alcohol. The IUPAC name is ethanol.
b. This compound has a four-carbon chain with a hydroxyl attached to carbon 2. The IUPAC
name is 2-butanol.
c. This compound has a six-carbon chain with a hydroxyl group attached to carbon 3. The
IUPAC name is 3-hexanol.
d. This compound has a four-carbon chain with a hydroxyl attached to carbon 1and a methyl
attached to carbon 3. The IUPAC name is 3-methyl-1-butanol.
e. This compound is a six-carbon cycloalkane with a hydroxyl attached to carbon 1 and two
methyl groups, one attached to carbon 3 and the other to carbon 4. Since the hydroxyl is
always attached to carbon 1 the number 1 is omitted in the name. The IUPAC name is
3,4-dimethylcyclohexanol.
f. This compound has a seven-carbon chain with a hydroxyl attached to carbon 1 and three
methyl groups, one attached to carbon 3 and two attached to carbon 5. The IUPAC name is
3,5,5-trimethyl-1-heptanol
14.4
a. 1-ethylcyclobutanol
c. 2,3-dimethyl-1-pentanol
e. 2,4-dimethylcyclopentanol
b. primary
e. primary
c. primary
b. 3-chloro-2-methyl-1-butanol
d. 5,5-dichloro-2-pentanol
f. 3-ethyl-1-pentanol
Chapter 14 Answers and Solutions
14.5
a. 1-propanol has a three-carbon chain with a hydroxyl attached to carbon 1.
CH3CH2CH2OH
b. Methyl alcohol has a hydroxyl attached to a one-carbon alkane CH3OH.
c. 3-pentanol has a five-carbon chain with a hydroxyl attached to carbon 3.
OH
|
CH3CH2CHCH2CH3
d. 2-methyl-2-butanol has a four-carbon chain with a methyl and hydroxyl attached to carbon 2.
OH
|
CH3CCH2CH3
|
CH3
OH
e. Cyclohexanol has a six-carbon cycloalkane with a hydroxyl attached.
f. 1,4-butanediol has a four-carbon chain (butane). The diol indicates that there are two
hydroxyl groups, one attached to carbon 1 and one to carbon 4.
HOCH2CH2CH2CH2OH
CH3
14.6
a. CH3CH2OH

b. CH3CHCH2CH2OH
OH
Cl
c.
d. CH3CH2CH2OH
Cl
CH3 OH CH3
OH
 

f. CH3CCHCHCH2CH3

CH3
e.
OH
14.7
A benzene ring with a hydroxyl group is called phenol. Substituents are numbered from the
carbon bonded to the hydroxyl group as carbon 1. Common names use the prefixes ortho,meta,
and para.
a. phenol
b. 2-bromophenol, ortho-bromophenol (Groups on the 1 and 2 positions are ortho)
c. 3,5-dichlorophenol
d. 3-bromophenol, meta-bromophenol (Groups on the 1 and 3 positions are meta)
14.8
a. 3-ethylphenol, m-ethylphenol
c. 3-chlorophenol, m-chlorophenol
b. 2,5-dibromophenol
d. 2-chlorophenol, o-chlorophenol
Alcohols, Phenols, Ethers, and Thiols
14.9
a. The m (meta) indicates that the two groups are in the 1,3 arrangement.
OH
OH
Br
b. The p (para) indicates that the two groups are in the 1,4 arrangement
Cl
c. Two chlorine atoms are attached to the aromatic system, one on carbon 2 and the other on
carbon 5, with the hydroxyl attached to carbon 1.
OH
Cl
Cl
d. The o (ortho) indicates that the two groups are in the 1,2 arrangement
OH
e. The name indicated that there is an ethyl group on carbon 4 with the hydroxyl on carbon 1.
OH
CH2CH3
14.10
OH
OH
a.
b.
Cl
c.
OH
CH2CH3
CH3
Cl
CH3
OH
OH
CH2CH3
d.
CH3
e.
Chapter 14 Answers and Solutions
14.11
a. This is a one-carbon alkane with a thiol (−SH) group. The IUPAC name is methanethiol.
b. This thiol has a three-carbon alkane with the thiol group attached to carbon 2. The IUPAC
name is 2-propanethiol
c. This compound has a four-carbon alkane with methyl groups attached to carbon 2 and carbon
3 and the thiol attached to carbon 1. The IUPAC name is 2,3-dimethyl-1-butanethiol.
d. This compound has a thiol attached to a cyclobutane. The IUPAC name is cyclobutanethiol.
14.12
a. 1-propanethiol
c. 2,2-dimethyl-1-propanethiol
14.13
a. ethanol
14.14
a. 1,2-ethanediol; ethylene glycol forms oxalic acid
b. BHA; butylated hydroxyanisole and BHT; butylated hydroxytoluene
c. 1,2,3-propanetriol; glycerol
14.15
a. methoxyethane; ethyl methyl ether
b. methoxycyclohexane, cyclohexyl methyl ether
c. ethoxycyclobutane, cyclobutyl ethyl ether
d. 1-methoxypropane, methyl propyl ether
14.16
a. 1-ethoxypropane, ethyl propyl ether
b.
b. 2-pentanethiol
d. cyclopentanethiol
thymol
c. ethoxycyclopentane, cyclopentyl ethyl ether
14.17
c. ortho-phenylphenol
b. methoxybenzene, methyl phenyl ether;
anisole
d. methoxymethane, dimethyl ether
a. Ethyl propyl ether has a two-carbon group and a three-carbon group attached to oxygen by
single bonds. CH3CH2OCH2CH2CH3
b. Ethyl cyclopropyl ether has a two-carbon group and a three-carbon cyclo alkyl group attached
to oxygen by single bonds.
CH3CH2O
c. Methoxycyclopentane has a one-carbon group and a five-carbon cycloalkyl group attached to
oxygen by single bonds.
OCH3
d. 1-ethoxy-2-methylbutane has a four-carbon chain with a methyl attached to carbon 2 and an
ethoxy attached to carbon 1.
CH3
|
CH3CH2−O−CH2CHCH2CH3
e. 2,3-dimethoxypentane has a five-carbon chain with two methoxy groups attached; one to
carbon 2 and the other to carbon 3.
OCH3
|
CH3CHCHCH2CH3
|
OCH3
Alcohols, Phenols, Ethers, and Thiols
14.18
a. CH3CH2−O−CH2CH3
b.
O
OCH2CH3
c.
CH3 CH3
 
d. CH3CCHCH3

OCH3
OCH3
OCH3
e.
14.19
a. Constitutional isomers (C5H12O) have the same formula, but different arrangements.
b. Different compounds have different molecular formulas.
c. Constitutional isomers (C5H12O) have the same formula, but different arrangements.
14.20
a. constitutional isomers
14.21
The heterocyclic ethers with five atoms including one oxygen are named furan; six atoms
including one oxygen are pyrans. A six-atom cyclic ether with two oxygen atoms is dioxane.
a. tetrahydrofuran
b. 3-methylfuran
c. 5-methyl-1, 3-dioxane
14.22
a. furan
14.23
a. methanol; hydrogen bonding of alcohols gives higher boiling points than alkanes.
b. 1-butanol; alcohols hydrogen bond, but ethers cannot.
c. 1-butanol; hydrogen bonding of alcohols gives higher boiling points than alkanes.
14.24
Glycerol can form more hydrogen bonds because it has three hydroxyl groups (OH)
compared to the hydrogen bond for one hydroxyl group in 1-pentanol.
14.25
a.
b.
c.
d.
e.
14.26
a. Ethanol contains a hydroxyl group (OH)
b. The oxygen in ethers can form hydrogen bonds with water.
c. Alcohols with one to four carbon atoms are soluble in water. In alcohols with longer carbon
chains, the effect of the OH group is diminished.
14.27
Dehydration is the removal of an −OH and a −H from adjacent carbon atoms.
b. constitutional isomers
b. 2-methyl-1,4-dioxane
c. constitutional isomers
c. 4-methylpyran
yes, alcohols with 1-4 carbon atoms hydrogen bond with water
yes; the water can hydrogen bond to the O in ether
no; a carbon chain longer than 4 carbon atoms diminishes the effect of the OH group.
no; alkanes are nonpolar and do not hydrogen bond
yes; the OH in phenol ionizes in water, which makes it soluble
a. CH3CH2CH=CH2
b.
c. In c, there are two possible products A and B. B will be the major product, since the hydrogen
is removed from the carbon that has the smaller number of hydrogens.
CH3
A
B
CH3
Chapter 14 Answers and Solutions
d. In d, there are two possible products A and B. B will be the major product, since the
hydrogen is removed from the carbon that has the smaller number of hydrogens.
CH3CH2CH2CH=CH2
CH3CH2CH=CHCH3
A
B
CH3
CH3

14.28
a. CH3C=CH2

b. CH3 CH=CCH2CH3
CH3
c.
14.29
d.
An ether is formed when H2O is eliminated from two alcohols; the alkyl portion of one alcohol
combines with the alkoxy portion of the other alcohol.
b. CH3CH2CH2OCH2CH2CH3
a. CH3OCH3
CH3
CH3


b. CH3CHCH2OCH2CHCH3
14.30
a. CH3CH2OCH2CH3
14.31
Alcohols can produce alkenes and ethers by the loss of water (dehydration).
a. CH3CH2OH
b. Since this ether has two different alkyl groups;,it must be formed from two alcohols.
CH3OH + CH3CH2OH
c.
14.32
14.33
OH
a. CH3CH2OH
CH3
CH3


b. CH3CCH2CH3 or CH3CHCHCH3


OH
OH
OH
c.
a. A primary alcohol oxidizes to an aldehyde and then to a carboxylic acid.
O
O
||
||
CH3CH2CH2CH2CH
then CH3CH2CH2CH2COH
O
||
b. A secondary alcohol oxidizes to a ketone. CH3CH2CCH3
c. A secondary alcohol oxidizes to a ketone.
O
Alcohols, Phenols, Ethers, and Thiols
O
CH3
||
|
d. A secondary alcohol oxidizes to a ketone. CH3CCH2CHCH3
e. A primary alcohol oxidizes to an aldehyde and then to a carboxylic acid.
O
CH3
O
CH3
||
|
||
|
CH3CHCH2CH then
CH3CHCH2COH
O
14.34
a.
C
OH
O
CH3

||
b. CH3CHCH2 CCH3
O
O O
|| ||
d. CH3CCCH2CH3
14.35
c. none
e.
a. An aldehyde is the product of the oxidation of a primary alcohol CH3 OH.
b. A ketone is the product of the oxidation of a secondary alcohol.
OH
OH
|
c. A ketone is the product of the oxidation of a secondary alcohol. CH3CHCH2CH3
d. An aldehyde is the product of the oxidation of a primary alcohol.
CH2OH
OH
e. A ketone is the product of the oxidation of a secondary alcohol.
CH3
a. CH3CH2OH
OH CH3
|
|
b. CH3CHCHCH3
d. CH3CH2CH2OH
CH3
|
e. CH3CHCH2CH2OH
14.37
a. 2°
c. 1°
14.38
a. tertiary
d. tertiary
14.36
b. 1°
b. tertiary
e. primary
d. 2°
c. primary
f. secondary
OH
c.
e. 1°
f. 3°
Chapter 14 Answers and Solutions
14.39
a. alcohol
e. ether
b. ether
f. cyclic ether
c. thiol
g. alcohol
d. alcohol
h. phenol
14.40
a. phenol
e. ether
b. thiol
f. cyclic ether
c. ether
g. phenol
d. alcochol
h. phenol
14.41
a.
c.
e.
g.
2-chloro-4-methylcyclohexanol
2-propanethiol
1-methoxypropane; methyl propyl ether
4-bromo-2-pentanol
b. methyoxy benzene; methyl phenyl ether
d. 2,4-dimethyl-2-pentanol
f. 3-methyl furan
h. meta-cresol
14.42
a.
c.
e.
g.
4-chlorophenol; p-chlorophenol
ethoxycyclopentane; cyclopentyl ethyl ether
3-methoxypentane
2,4-dichlorophenol
b.
d.
f.
h.
1-propanethiol
2,4-dimethyl-2-pentanol
1.4-dioxane
3,4-dimethylphenol
14.43
OH
OH
a.
b.
CH3
c.
H3C
CH3
OH
CH
CH
Cl
O
d.
CH2
CH2
CH3
CH3
SH
e. CH3 CH2
CH
CH2
f.
CH3
CH3
OH
OH
Br
g.
Br
14.44
OCH3
|
a. CH3CH2CHCH2CH3
OH OH
|
|
c. CH3CHCHCH2CH3
OH CH3
|
|
f. CH3CHCHCH3
OH
b.
Cl
d. CH3CH2CH2OCH3
OH
g.
Cl
Cl
e. CH3SH
Alcohols, Phenols, Ethers, and Thiols
14.45
a. Glycerol is used in skin lotions.
b. 1,2-ethanediol; ethylene glycol is used in antifreeze
c. Ethanol is produced by fermentation of grains and sugars.
14.46
a. methanol
14.47
Write the carbon chain first, and place the OH on the carbon atoms in the chain to give
different structural formulas. Shorten the chain by one carbon, and attach a methyl group and
OH group to give different compounds.
OH
|
CH3CH2CH2CH2OH CH3CHCH2CH3
b. 2-propanol; isopropyl alcohol
CH3
|
CH2CHCH2OH
14.48
OH
|
CH2CCH3
|
CH3
CH3OCH2CH2CH2CH3
CH3
|
CH3OCH2CHCH3
CH3
|
CH3OCCH3
c. ethanol
CH3CH2OCH2CH2CH3
CH3
|
CH3CH2OCHCH3
CH3
|
CH3OCHCH2CH3
14.49
a. 1-propanol; hydrogen bonding
c. 1-butanol; larger molar mass
b. 1-propanol; hydrogen bonding
14.50
a. ethyl alcohol
c. 1-butanol
14.51
a.
c.
a.
c.
14.52
14.53
b. 2-pentanol
soluble; hydrogen bonding
b. soluble; hydrogen bonding
insoluble; long carbon chain diminishes effect of polar OH on hydrogen bonding
soluble; three OH groups
b. insoluble; nonpolar hydrocarbon
soluble; two OH groups makes longer hydrocarbon chain more soluble in water
a. CH3CH=CH2
O
||
b. CH3CH2CH
O
c. CH3CH=CHCH3
||
d. CH3CH2CCH3
e. CH3CH2CH2O CH2CH2CH3
O
f.
g.
Chapter 14 Answers and Solutions
14.54
CH3
|
a. CH3C=CH2
CH3
|
b. CH3C=CHCH3
CH3 O
|
||
c. CH3CHCCH3
CH3
d.
O
CH3
f. CH3CH2OCH2CH3
e.
g. CH3CH2CH=CHCH3
14.55
Cl
|
H+, heat
a. CH3CH2CH2OH → CH2CH=CH2 + HCl → CH3CHCH3
OH
H+, heat
Pt
→ CH3C=CH2 + H2 → CH3CHCH3
|
|
CH3
CH3
OH
H+
|
H+, heat
c. CH3CH2CH2OH → CH3CH=CH2 + H2O → CH3 CHCH3
|
b. CH3CCH3
|
CH3
O
||
[O]
→ CH3CCH3
14.56
a. CH3CH2CH2CH2CH2OH
b.
OH
H+, heat
→ CH3CH2CH2CH=CH2
Cl
H
+
HCl
H+, heat
c. CH3CH2CH2CH2OH → CH3CH2CH=CH2 + Cl2 →
Cl
|
CH3CH2CHCH2Cl
14.57 Testosterone contains cycloalkene, alcohol and ketone functional groups.
14.58
a. cycloalkene, phenol, ether
b. cycloalkene, ketone, alcohol, alkyne
Alcohols, Phenols, Ethers, and Thiols
14.59 4-hexyl-1, 3-benzenediol tells us that there is a six carbon group attached to carbon 4 of a benzene
OH
ring and hydroxyls attached to carbons 1 and 3.
OH
CH2CH2CH2CH2CH2CH3
14.60
Menthol is 2−isopropyl−5−methylcyclohexanol. Thymol is 2−isopropyl−5−methylphenol.
They have the same groups in the same position, but thymol is aromatic, while menthol is a
cyclic alcohol.
14.61
a. 2,5-dichlorophenol is a benzene ring with a hydroxyl on carbon 1 and chlorine atoms on
carbons 2 and 5.
OH
Cl
Cl
CH3
b.
CH3
CH
CH3
CH2
CH2
SH
H
H
C
C
CH2
SH
OH
c.
Cl
Cl
Cl
Cl
Cl
14.62
b.p. −24°C
Dimethyl ether
CH3OCH3
Ethyl alcohol
CH3CH2OH
b.p. 79°C
The polar hydroxyl groups in ethyl alcohol form hydrogen bonds between the alcohol
molecules, which requires a higher boiling point to separate them into gaseous molecule