pH + pOH = pK
w
pK
a
+ pK
b
= pK
w
K
a
K
b
= K
w
pH = pK
a
+ log (c
b
/c
a
)
pH= pK
a
+ log (n
b
/n
a
)
pK
w
= 14.00
1.
The conjugate acid of HCO
3
–
is
A.
CO
3
2–
B.
H
3
O
+
C.
H
2
CO
3
D.
HCO
3
–
E.
H
2
O
2.
Which of the following is the strongest acid?
A.
HF (p
K
a
= 3.45)
B.
CH
3
COOH (p
K
a
= 4.75)
C.
HClO
2
(p
K
a
= 2.00)
D.
HCN (p
K
a
= 9.31)
E.
HNO
2
(p
K
a
= 3.37)
3.
Which of the following produces the strongest conjugate base?
A.
HCN (p
K
a
= 9.31)
B.
CH
3
COOH (p
K
a
= 4.75)
C.
HClO (p
K
a
= 7.53)
D.
HF (p
K
a
= 3.45)
E.
HCOOH (p
K
a
= 3.75)
4.
If a small amount of HCl(aq) is added to 0.10 M NH
3
(aq),
A.
the equilibrium concentration of NH
4
+
(aq) is increased.
B.
K
a
becomes larger.
C.
no change occurs.
D.
the equilibrium concentration of NH
4
+
(aq) is decreased.
E.
the equilibrium concentration of NH
3
(aq) increases.
5.
Which of the following is the strongest acid?
A.
H
2
O
B.
H
2
Te
C.
CH
4
D.
H
2
Se
E.
H
2
S
6.
The pH of 0.10 M CH
3
COOH(aq) is 2.87. What is the percent ionization of CH
3
COOH?
A.
5.0%
B.
0.13%
C.
10%
D.
13%
E.
1.3%
7.
What is the pH of 1.0 M HCNO(aq) (
K
a
= 2.2
´
10
–4
)?
A.
7.32
B.
4.70
C.
3.66
D.
7.00
E.
1.83
8.
The pH of 0.10 M pyridine(aq) is 9.13. What is the value of
K
b
for pyridine?
A.
2.7
´
10
–5
B.
1.8
´
10
–6
C.
2.7
´
10
–4
D.
1.8
´
10
–9
E.
7.4
´
10
–10
9.
What is the pH of 0.010 M NH
2
NH
2
(aq) (p
K
b
= 5.77)?
A.
10.11
B.
11.12
C.
12.00
D.
8.23
E.
12.13
10.
Calculate the pH of 0.050 M H
2
S(aq) (p
K
a1
= 6.88, p
K
a2
= 14.15).
A.
4.09
B.
6.88
C.
7.12
D.
2.79
E.
3.44
11.
Which one of the following salts gives a basic aqueous solution?
A.
KCN
B.
NaBr
C.
NH
4
ClO
4
D.
CuCl
2
E.
NaNO
3
12.
Calculate the pH of a 0.136 M solution of aqueous sodium fluoride. The value of
K
a
for HF is 3.5
´
10
–4
.
A.
8.29
B.
5.71
C.
8.73
D.
2.16
E.
11.84
13.
The curve for the titration of 50.0 mL of 0.0200 M HClO(aq) with 0.100 M NaOH(aq) is given below. Estimate the p
K
a
of HClO.
A.
4.0
B.
10.0
C.
12.0
D.
5.0
E.
7.5
14.
For the titration of 50.0 mL of 0.020 M aqueous salicylic acid with 0.020 M KOH(aq), calculate the pH after the addition of 55.0 mL of KOH(aq). For salycylic acid, p
K
a
= 2.97.
A.
10.98
B.
12.30
C.
11.26
D.
12.02
E.
7.00
15.
Which of the following indicators would be most suitable for the titration of 0.10 M HBr(aq) with 0.10 M KOH(aq)?
A.
alizarin yellow (p
K
In
= 11.2)
B.
methyl orange (p
K
In
= 3.4)
C.
bromophenol blue (p
K
In
= 3.9)
D.
thymol blue (p
K
In
= 1.7)
E.
bromothymol blue (p
K
In
= 7.1)
16.
For NH
3
, p
K
b
= 4.74. What is the pH of an aqueous buffer solution that is 0.050 M NH
3
(aq) and 0.20 M NH
4
Cl(aq)?
A.
9.86
B.
8.66
C.
5.34
D.
9.26
E.
4.14
17.
If the value of the solubility product for AgBr is 5.0
´
10
–13
at 25°C, calculate the solubility of AgBr(s) in water.
A.
5.0
´
10
–7
B.
7.1
´
10
–7
C.
1.4
´
10
–6
D.
2.5
´
10
–13
E.
2.5
´
10
–6
18.
If equal volumes of 0.1 M Pb(NO
3
)
2
(aq) and 0.2 M KI(aq) are mixed, what reaction, if any, occurs? The value of
K
sp
for PbI
2
is 1.4
´
10
–8
.
A.
KNO
3
(s) precipitates
B.
no reaction occurs
C.
PbI
2
(s) precipitates
D.
the solution turns purple due to formation of I
2
E.
K
sp
changes to 5
´
10
–4
19.
Which of the following water–insoluble salts is much more soluble in 1.0 M HClO
4
(aq)?
A.
PbCO
3
B.
PbI
2
C.
Hg
2
Br
2
D.
AgI
E.
AgCl
20.
The solubility of CuI in H
2
O is improved by
A.
addition of NH
3
.
B.
addition of HNO
3
.
C.
addition of NaI.
D.
None of the answers are correct.
E.
More than one of the answers are correct.
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