CHEM 122
HW CH#10 ACIDS W14
10-6
Of these four carboxylic acids with molecular formula C5H10O2, only one is chiral. Its stereocenter is
identified with an asterisk.
COOH
Pentanoic acid
COOH
3-Methylbutanoic
acid
*
COOH
2-Methylbutanoic
acid
COOH
2,2-Dimethylpropanoic acid
10-8
(a)
2-Hydroxybutanedioic acid
(b) 2-Hydroxybenzoic acid
(c) Trichloroacetic acid
10-16
If you draw this molecule correctly to show this internal hydrogen bonding, you will see that the
hydrogen-bonded part of the molecule forms a six-membered ring.
H2C
H
C
O
O
C
O
H 
O
H2C
C
O
O
C
O
H 
O

H
10-20
In order of increasing boiling point, they are diethyl ether (b.p. 35°C), 1-butanol (b.p. 117°C), and
propanoic acid (b.p. 141°C). Boiling points increase as the degree of intermolecular hydrogen
bonding increases.
10-24
Soaps and detergents contain both hydrophilic and hydrophobic components. The hydrophobic
components cluster inward and form micelles when placed into water. Nonpolar grease and dirt
dissolve in the nonpolar inner part of the micelle. The hydrophilic portion of the detergent
favorably interacts with water to aid in emulsifying the dirt and grease in water.
ionic, hydrophilic
Cl
N
H3C
CH3
nonpolar, hydrophobic
polar, hydrophilic
HO CH2
polar, hydrophilic
O
HO CH2 C CH2 O C (CH2)14CH3
HO CH2
nonpolar, hydrophobic
10-36
The pKa of ascorbic acid is 4.10. At this pH, ascorbic acid is present 50% as ascorbic acid and 50%
as ascorbate ion. At pH 7.35 to 7.45, which is more basic than pH 4.10, ascorbic acid would be
present as ascorbate ion.
10-38
CH3CH2NH2 is the stronger base. The electron lone pair on the less electronegative nitrogen is
more basic relative to the electrons stabilized by resonance in the carboxylate anion.
10-40
Fischer esterification is the process of forming an ester by treating a carboxylic acid with an
alcohol in the presence of an acid catalyst, commonly sulfuric acid. An example is the formation
of ethyl acetate from acetic acid and ethanol.
O
CH3C-OH + HOCH2CH3
Acetic acid
Ethanol
H2SO4
O
CH3COCH2CH3 + H2O
Ethyl acetate
10-44
Cinnamic acid reacts with the following reagents to accomplish the following syntheses:
O
H2
Ni
OH
1. LiAlH4
2. H2O
OH
O
OH
CH3CH2OH
H+
O
OCH2CH3