134
CHA PTE R 3
Acids and Bases
3.12
I
DENTIFYIN
G L
E
W
IS
A
CIDS
AND
L
E
W
IS
B
ASES
STEP
1
Identify the direction
of the flow of elect
ro
ns.
H
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
H
H
+
To here From here
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
STEP 2
Identify the electron acceptor as the Lewis acid
and the electron donor as the Lewis base.
H
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
H
H
+
Acceptor Donor
Lewis acid Lewis base
O
O
O
O
O
O
OO
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
OOO
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
Try Problems
3.34, 3.35, 3.39
Note: Most of the Problems are available within ,
an online teaching and learning solution.
3.36
Draw the conjugate base for each of the following acids:
(a)
OH
(b)
O
(c)
NH
3
(d)
H
3
O
+
(e)
OH
O
(f
)
N
H
(g)
NH
4
+
3.37
Draw the conjugate acid for each of the following bases:
(a)
@
(b)
O
@
(c)
NaNH
2
(d)
H
2
O
(e)
OH
(f
)
NH
2
(g)
O
(h)
NaOH
3.38
Compound A has a p
K
a
K
K
of 7 and compound B has a p
K
a
K
K
of 10.
Compound A is how many times more acidic than compound B?
(a)
3
(b)
3000
(c)
1000
3.39
In each reaction, identify the Lewis acid and the Lewis base:
(a)
OH
+
O
H
!
!
(b)
OH
F
B
F
F
+
F
B
F
F
O
H
@
!
(c)
Cl
Al
Cl
Cl
+
Cl
Cl
Al
Cl
Cl
Cl
@
!
3.40
What reaction will take place if H
2
O is added to a mixture of
NaNH
2
/NH
3
?
3.41
Would ethanol (CH
3
CH
2
OH) be a suitable solvent in which to
perform the following proton transfer? Explain your answer:
+
+
NH
3
H
NH
2
@
@
3.42
Would water be a suitable proton source to protonate the fol
-
lowing compound?
ONa
O
3.43
Write an equation for the proton transfer reaction that occurs
when each of the following acids reacts with water. In each case, draw
curved arrows that show the mechanism of the proton transfer:
(a)
HBr
(b)
H O
H O
S
O
O
O
H
(c)
O
H
!
3.44
Write an equation for the proton transfer reaction that occurs
when each of the following bases reacts with water. In each case, draw
curved arrows that show the mechanism of the proton transfer:
(a)
@
(b)
O
@
(c)
@
(d)
N
@
3.45
In each case, identify the more stable anion. Explain why it is
more stable:
(a)
vs.
@
@
(b)
vs.
N
@
@
(c)
vs.
@
@
3.46
In each group of compounds below, select the most acidic
compound:
(a)
N
H
N
H
(b)
O
O
O
O
Cl
Cl
Cl
PRACTICE PROBLEMS
