Chapter 19 Values
The following equilibrium constants will be useful for the problems in this chapter.
Substance Constant Substance Constant
HCO2H Ka = 1.8 104 H2CO3 K1 = 4.2 107
HNO2 Ka = 4.5 104 K2 = 4.8
...
Chapter 19 Values
The following equilibrium constants will be useful for the problems in this chapter.
Substance Constant Substance Constant
HCO2H Ka = 1.8 104 H2CO3 K1 = 4.2 107
HNO2 Ka = 4.5 104 K2 = 4.8 1011
HOCl Ka = 3.5 108
(COOH)2 K1 = 5.9 102
HF Ka = 7.2 104 K2 = 6.4 105
HCN Ka = 4.0 1010 CH3COOH Ka = 1.8 105
H2SO4 K1 = very large HOCN Ka = 3.5 104
K2 = 1.2 102 C6H5NH2 Kb = 4.2 1010
HOBr Ka = 2.5 109 NH3 Kb = 1.8 105
1. A(n) ____ solution contains a conjugate acid-base pair with both the acid and the base in reasonable
concentrations.
a. saturated
b. electrolytic
c. buffer
d. titrated
e. equivalence
ANS: C
OBJ: Identify a description of a buffer.
TOP: The Common Ion Effect and Buffer Solutions
2. When a solution of weak electrolyte is altered by adding one of its ions from another source, the
ionization of the weak electrolyte is suppressed. This behavior is termed the ____.
a. common ion effect
b. buffer effect
c. titration curve
d. equivalence point
e. partial neutralization effect
ANS: A
OBJ: Identify a description of the common ion effect.
TOP: The Common Ion Effect and Buffer Solutions
3. The pH of a 0.03 M formic acid (HCOOH) solution is 2.63. If 0.03 M sodium formate (NaHCOO) is
added, which of the following statements is true?
a. The pH decreases.
b. The equilibrium position is shifted to the left.
c. The [H3O
+
] increases.
d. The [HCOOH] decreases.
e. None of these are true.
ANS: B
OBJ: Identify a consequence of the common ion effect.
TOP: The Common Ion Effect and Buffer Solutions
Whitten 10e Test Bank
Whitten 10e Test Bank
4. What is the [H3O
+
] of a solution that is 0.0100 M in HOCl and 0.0300 M in NaOCl?
a. 2.14 107 M
b. 1.45 107 M
c. 7.41 108 M
d. 2.29 108 M
e. 1.17 108 M
ANS: E
OBJ: Calculate the hydronium ion concentration of a buffer.
TOP: The Common Ion Effect and Buffer Solutions
5. Calculate the [H3O
+
] of a solution that is 0.20 M in HF and 0.10 M in NaF.
a. 3.2 104 M
b. 4.0 106 M
c. 1.4 103 M
d. 6.3 105 M
e. 5.0 103 M
ANS: C
OBJ: Calculate the hydronium ion concentration of a buffer.
TOP: The Common Ion Effect and Buffer Solutions
6. Calculate the pH of a solution that is 0.20 M in sodium hypobromite and 0.10 M in hypobromous acid.
a. 4.15
b. 4.45
c. 8.60
d. 8.90
e. 8.30
ANS: D
OBJ: Calculate the pH of a buffer.
TOP: The Common Ion Effect and Buffer Solutions
7. Calculate the pH of a solution that is 0.15 M in HOCl and 0.25 M in NaOCl.
a. 7.23
b. 8.28
c. 8.06
d. 7.68
e. 9.10
ANS: D
OBJ: Calculate the pH of a buffer.
TOP: The Common Ion Effect and Buffer Solutions
8. What is the pH of a solution which is 0.0400 M in formic acid, HCO2H, and 0.0600 M in sodium
formate, NaHCOO?
a. 3.92
b. 3.96
c. 4.00
d. 9.52
e. 4.08
ANS: A
OBJ: Calculate the pH of a buffer
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