Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
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1. Acids and bases are defined by their donation or acceptance of a proton, according to the
a. Arrhenius model
b. Brønsted-Lowry model
c. Lewis model
d. all of these
e. none of these
2. Acids and bases are defined by their acceptance or donation of an electron pair, according to the
a. Arrhenius model
b. Brønsted-Lowry model
c. Lewis model
d. all of these
e. none of these
3. Acids and bases are defined by their production of hydronium or hydroxide ions when dissolved in water,
according to the
a. Arrhenius model
b. Brønsted-Lowry model
c. Lewis model
d. all of these
e. none of these
4. Which of the following represents a conjugate Brønsted-Lowry acid-base pair?
a. H3PO4 and HPO42b. H2SO4 and SO42c. NH3 and NH2d. all of these
e. none of these
5. In the Brønsted-Lowry acid-base reaction between methylamine (CH3NH2) and sulfuric acid, one of the
products is
a. SO3(g)
b. NH3(g)
c. CH3NH-(aq)
d. CH3NH3+(aq)
e. none of these
6. For an aqueous solution at 25°C, if [H3O+] = 0.050 m, then [OH-] =
a. 2.0 10-12 m
b. 1.0 10-7 m
c. 2.0 10-6 m
d. 5.0 10-2 m
e. none of these
7. Strong acids all exhibit essentially the same strength in aqueous solution. This is because
a. there are no intrinsic acidity differences among the strong acids.
b. strong acids are all essentially 100% ionized to H3O+(aq) in water.
c. there is no OH-(aq) present in an aqueous solution of a strong acid.
d. All of these are correct.
e. None of these is correct.
8. In a sample of orange juice at 25°C, [H3O+] = 1.78 10-3 m. The pH of the juice is therefore
a. 2.22
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9.
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b. 2.75
c. 3.25
d. 6.33
e. none of these
What is the pH of a 0.25 m aqueous HCl solution at 25°C?
a. 0.60
b. 1.39
c. 1.78
d. 2.50
e. none of these
For a 2.3 m solution of nitric acid at 25°C, the calculated pH is
a. -0.83
b. -0.36
c. 0.00
d. 0.36
e. none of these
For a 2.6 10-10 m aqueous sodium hydroxide solution at 25°C, the approximate pH is
a. 3.85
b. 4.41
c. 7.00
d. 9.58
e. none of these
What is the concentration of OH- in an aqueous solution with a pH of 1.75 at 25°C?
a. 5.6 10-13 m
b. 1.8 10-12 m
c. 1.8 10-2 m
d. 5.6 10-1 m
e. none of these
Two HCl(aq) solutions have pH = 2.00 and pH = 3.00, respectively. If equal volumes of these two solutions are
combined, the pH of the resulting solution will be
a. 1.96
b. 2.26
c. 2.50
d. 2.69
e. none of these
An aqueous perchloric acid solution of pH 1.80 is diluted with water to 1.60 times its original volume. The pH
of the resulting solution is
a. 1.12
b. 1.60
c. 2.00
d. 2.88
e. none of these
When the temperature is reduced from 25°C to 10°C, the value of Kw changes from 1.0 10-14 to 2.910-15. The
change implies that the reaction, 2 H2O(l) H3O + (aq) + OH-(aq), must be
a. endothermic
b. exothermic
c. neither endothermic nor exothermic
d. unpredictable
e. none of these
____ 16. If Kw is 2.9 10-15 at 10°C, what is the pH of pure water at 10°C?
a. 6.72
b. 7.00
c. 7.27
d. 7.53
e. none of these
____ 17. The value of Ka for strong acids can be estimated if water is replaced by a solvent that is
a. more volatile.
b. less volatile.
c. a stronger base.
d. a weaker base.
e. none of these
____ 18. Which of the following pKa values belongs to the weakest acid?
a. 3.18
b. 3.35
c. 7.04
d. 7.53
e. This cannot be determined from the given information.
____ 19. If an acid has Ka = 4.93 10-10, then Kb for the conjugate base is
a. 5.17 10-10
b. 9.95 10-8
c. 2.03 10-4
d. 5.17 10-4
e. none of these
____ 20. Which of the following Ka values belongs to the acid with the strongest conjugate base?
a. 4.3 10-7
b. 5.0 10-7
c. 1.9 10-5
d. 6.5 10-5
e. This cannot be determined from the given information.
____ 21. If Ka = 7.5 10-3 for a certain acid, then for its conjugate base, pKb =
a. -2.12
b. 2.12
c. 7.50 10-12
d. 10-11.88
e. none of these
____ 22. If Kb = 2.08 10-4 for a certain base, then for its conjugate acid, pKa =
a. 3.68
b. 4.28
c. 6.36
d. 10.32
e. none of these
____ 23. An example of a polyprotic oxoacid is
a. H2SO3(aq)
b. H2S(aq)
c. HClO3(aq)
d. all of these
e. none of these
____ 24. The K for the reaction, F-(aq) + H2O(l) HF(aq) + OH-(aq), is called
a. Ka for Fb. Ka for HF
c. Kb for Fd. Kb for HF
e. none of these
____ 25. For the reaction, NH3(aq) + H3O+ NH4 + (aq) + H2O(l), the equilibrium constant K is
a. Ka for NH3
b. Ka for NH4+
c. Kb for NH3
d. Kb for NH4+
e. none of these
____ 26. The reaction, HX(aq) + F-(aq) HF(aq) + X-(aq), has K = 0.024. Thus, the stronger acid and the stronger base
are
a. HX and Fb. HX and Xc. HF and Fd. HF and Xe. This cannot be determined from the given information.
____ 27. If Kal for oxalic acid (H2C2O4) is 5.910-2 and Kal for phosphoric acid is 7.5 10-3, what is the value of the
equilibrium constant for the reaction,
HC2O4-(aq) + H3PO4(aq) H2C2O4(aq) + H2PO4-(aq)
a. 0.079
b. 0.13
c. 1.3
d. 7.9
e. none of these
____ 28. An aqueous acetic acid solution and an aqueous perchloric acid solution are found to have the same pH at 25°C.
If equal volumes of each are used to neutralize a KOH(aq) solution, which of the following statements will be
true?
a. The acetic acid will neutralize a larger volume of the KOH(aq) solution.
b. The perchloric acid will neutralize a larger volume of the KOH(aq) solution.
c. Both acids will neutralize the same volume of the KOH(aq) solution.
d. The two solutions cannot have the same pH.
e. None of the statements is correct.
____ 29. Consider the weak acid phenol (C6H5OH), for which Ka = 1.05 10-10 in aqueous solutions at 25°C. What is the
pH of a 0.850 m aqueous phenol solution at 25°C?
a. 4.02
b. 5.02
c. 8.95
d. 9.98
e. none of these
____ 30. Consider the weak acid phenol (C6H5OH), for which Ka = 1.05 10-10 in aqueous solutions at 25°C. What
percentage of the phenol is ionized in a 0.500 m aqueous solution at 25°C?
a. 0.00145%
b. 0.00724%
c. 0.0145%
d. 0.0724%
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e. none of these
Consider the weak acid phenol (C6H5OH), for which Ka = 1.05 10-10 in aqueous solutions at 25°C. If 100.0 mL
of a 0.5000 m aqueous phenol solution is mixed with 100.0 mL of 0.5000 m aqueous sodium hydroxide at 25°C,
the resulting solution will have pH
a. 7.00
b. <7.00
c. >7.00
d. This cannot be predicted from the given information.
e. none of these
Which of the following aqueous solutions will have the largest percent ionization at 25°C if the pKa of acetic
acid is 4.75 and the pKa of propionic acid is 4.87?
a. 0.100 m acetic acid
b. 0.200 m acetic acid
c. 0.100 m propionic acid
d. 0.200 m propionic acid
e. This cannot be predicted from the given information.
What is the pH of a 0.60 m aqueous hydroxylamine solution at 25°C? (Hydroxylamine (HONH2) is a weak
base, for which Kb = 1.1 10-8 at 25°C.)
a. 6.9
b. 7.9
c. 8.9
d. 9.9
e. none of these
Calculate [H3O+] for a 4.310-3 m solution of nitrous acid (Ka = 4.610-4).
a. 0.021 m
b. 0.0043 m
c. 0.0014 m
d. 0.0012 m
e. none of these
Aniline (C6H5NH2) is a weak base. At 25°C, a 0.100 m aqueous solution has a pH of 8.80. The Kb of aniline is
a. 4.0 10-12
b. 4.0 10-11
c. 4.0 10-10
d. 1.6 10-9
e. none of these
Which of the following compounds will produce a basic 0.100 m aqueous solution at 25°C?
a. NaF
b. NH4Cl
c. NaCl
d. all of these
e. none of these
Which of the following compounds will produce an acidic 0.100 m aqueous solution at 25°C?
a. KCN
b. KNO3
c. KHSO3
d. all of these
e. none of these
Calculate the pH of a 0.100 m aqueous solution of sodium azide (NaN3) at 25°C, if the Ka for HN3 is 1.9 10-5.
a. 2.86
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b. 8.86
c. 9.36
d. 9.86
e. none of these
Consider the diprotic acid H2X, where Ka1 = 2.0 10-5 and Ka2 = 4.0 10-12 at 25°C. The concentration of
HX-(aq) in a 0.100 m solution of H2X at 25°C is approximately
a. 2.0 10-5 m
b. 1.4 10-3 m
c. 4.5 10-3 m
d. 1.4 10-2 m
e. none of these
The pH of a normal raindrop is 5.6. Given that for H2CO3, pKa1 = 6.37 and pKa2 = 10.32, calculate the
equilibrium ratio [HCO3-]/[H2CO3] in such a raindrop.
a. 0.17
b. 0.88
c. 1.62
d. 8.3
e. none of these
Consider a buffer composed of aqueous NH4Cl and NH3 at 25°C. Ka for ammonium ion is 5.6 10-10 at this
temperature. The concentration of NH4+(aq) and NH3(aq) would be equal in a buffer solution with a pH equal to
a. 4.63
b. 4.75
c. 7.00
d. 9.25
e. none of these
Consider a buffer composed of aqueous NH4Cl and NH3 at 25°C. Ka for ammonium ion is 5.6 10-10 at this
temperature. The NH4+/NH3 buffer system could be used to prepare an effective buffer at a pH equal to
a. 3.00
b. 5.00
c. 7.00
d. all of these
e. none of these
Consider a buffer composed of aqueous NH4Cl and NH3 at 25°C. Ka for ammonium ion is 5.6 10-10 at this
temperature. The pH of a solution containing 0.900 mol of NH4Cl and 1.60 mol of NH3 in 1.00 L of water is
a. 8.50
b. 9.00
c. 9.50
d. 10.00
e. none of these
Consider a buffer composed of aqueous NH4Cl and NH3 at 25°C. Ka for ammonium ion is 5.6 10-10 at this
temperature.If 0.250 mol of HCl is added to 1.00 L of an aqueous buffer solution containing 0.500 mol of
NH4Cl and 0.500 mol of NH3 at 25°C, the pH of the resulting solution will be
a. 6.25
b. 8.77
c. 9.25
d. 9.73
e. none of these
Consider a buffer composed of aqueous NH4Cl and NH3 at 25°C. Ka for ammonium ion is 5.6 10-10 at this
temperature. Which of the following combinations of reagents will produce an NH4+/NH3 buffer with pH 8.85?
a. 1.00 mol of NH4Cl and 0.400 mol of NH3
b. 1.40 mol of NH4Cl and 0.400 mol of NaOH
c. 1.00 mol of HCl and 1.40 mol of NH3
d. all of these
e. none of these
____ 46. What volume of 0.155 m KOH must be added to 50.00 mL of 0.100 m acetic acid (Ka = 1.7610-5) to give a
solution having a pH of 4.52? (Assume that volumes are additive.)
a. 7.69 mL
b. 11.88 mL
c. 32.26 mL
d. 50.0 mL
e. none of these
Figure 08-01
____ 47. Refer to Figure 08-01. The curve is most likely the result of the titration of a
a. strong acid with a strong base.
b. strong base with a strong acid.
c. weak acid with a strong base.
d. weak base with a strong acid.
e. strong base with a salt.
____ 48. Refer to Figure 08-01. The point where the titration mixture has the greatest buffering capacity is labeled
a. A
b. B
c. C
d. D
e. E
____ 49. Which of the following can serve as a Lewis base?
a. B(OH)3
b. N(CH3)3
c. Ag+
d. all of these
e. none of these
____ 50. 0.10 mole of NaNH2(s) is dissolved in enough water to make 1.00 L of solution. Which of the following is not
present in the final solution at approximately the indicated concentration?
a. [NH2-] = 0.1 m
b. [Na+] = 0.1 m
c. [NH3] = 0.1 m
d. All of these are present at roughly these concentrations.
e. None of these is present at the indicated concentration.
MULTIPLE CHOICE
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
B
C
A
C
D
E
B
B
A
B
C
A
B
C
A
C
D
D
E
A
E
D
A
C
E
D
B
A
B
A
C
A
D
D
C
A
C
B
B
A
D
E
C
44.
45.
46.
47.
48.
49.
50.
B
D
B
D
B
B
A