Chemistry, 6e (McMurry/Fay)
Chapter 14 Aqueous Equilibria: Acids and Bases
14.1 Multiple-Choice Questions
1) An Arrhenius acid is best defined as a
A) hydroxide donor.
B) proton acceptor.
C) substance that dissociates in water to produce aqueous hydrogen ions.
D) substance that dissociates in water to produce aqueous hydroxide ions.
2) When dissolved in water, which of the following compounds is an Arrhenius acid?
A) HCN
B) NaOH
C) NaF
D) CH3CH2OH
3) An Arrhenius base is best defined as a
A) proton donor.
B) hydroxide acceptor.
C) substance that dissociates in water to produce aqueous hydrogen ions.
D) substance that dissociates in water to produce aqueous hydroxide ions.
4) When dissolved in water, which of the following compounds is an Arrhenius base?
A) CH3OH
B) HOCl
C) KOH
D) KCl
5) A Br∅nsted-Lowry acid is best defined as a substance that can
A) accept a hydroxide ion.
B) donate a hydroxide ion.
C) accept a proton.
D) donate a proton.
6) Which one of the following species acts as a Br∅nsted-Lowry acid in water?
A) NaH
B) NH4+
C) CH3NH2
D) C6H6
7) In the following chemical equation indicate the reactant that is a Br∅nsted-Lowry acid.
HCN(aq) + H2O(l) ⇌ H3O+(aq) + CN–(aq)
A) HCN
B) H2O
C) H3O+
D) CN–
8) Indicate all the Br∅nsted-Lowry acids in the following chemical reaction.
HCl(aq) + H2O(aq) ⇌ H3O+(aq) + Cl–(aq)
A) HCl, H2O
B) HCl, H3O+
C) HCl, Cl–
D) HCl, H2O, H3O+
9) What are the Br∅nsted-Lowry bases in the following chemical reaction?
C5H5N(aq) + H2O(l) ⇌ C5H5NH+(aq) + OH-(aq)
A) C5H5N, H2O
B) C5H5N, C5H5NH+
C) C5H5N, OH–
D) C5H5N, H2O, OH–
10) What are the Br∅nsted-Lowry acids in the following chemical reaction?
HBr(sol) + CH3COOH(sol) ⇌ CH3C(OH)2+(sol) + Br–(sol)
A) HBr, CH3COOH
B) HBr, CH3C(OH)2+
C) CH3COOH, CH3C(OH)2+
D) CH3COOH, Br–
11) What are the conjugate acid-base pairs in the following chemical reaction?
NH3(aq) + H2O(l) ⇌ NH4+(aq) + OH–(aq)
A) NH3, H2O and NH4+, OH–
B) NH3, NH4+ and H2O, OH–
C) NH3, OH– and H2O, NH4+
D) NH3 and NH4+
12) Identify the conjugate acid/base pairs present in an aqueous solution of hydrogen sulfate ion,
HSO4–.
A) HSO4–/SO42- and H3O+/H2O
B) H2SO4/HSO4– and H2O/OH–
C) HSO4–/H2O and H3O+/SO42-
D) HSO4–/H2O and H2SO4/OH–
13) What is the conjugate base of the Br∅nsted-Lowry acid HPO42-?
A) H3PO4
B) H2PO4–
C) HPO42-
D) PO43-
14) What is the conjugate acid of the Br∅nsted-Lowry base HAsO42-?
A) H2AsO4–
B) AsO43-
C) H2O
D) H3O+
15) Which one of the following can behave either as a Br∅nsted-Lowry acid or a Br∅nsted-Lowry base
in an aqueous solution reaction?
A) HSO3–
B) NH3
C) HI
D) H3PO4
16) Write a balanced equation for the dissociation of the Br∅nsted-Lowry acid HSO4– in water.
A) HSO4–(aq) + H2O(l) ⇌ H2SO4(aq) + OH–(aq)
B) HSO4–(aq) + H2O(l) ⇌ SO42-(aq) + H3O+(aq)
C) HSO4–(aq) + H2O(l) ⇌ SO32-(aq) + OH–(aq)
D) HSO4–(aq) + H2O(l) ⇌ SO3(g) + OH–(aq) + H2O(l)
17) Which of the following Br∅nsted-Lowry acids does not behave as a strong acid when it is dissolved
in water?
A) HBr
B) HCl
C) HNO2
D) HClO4
18) Which Br∅nsted-Lowry base has the strongest conjugate acid?
A) CH3CO2–
B) CN–
C) F–
D) NO3–
19) Which Br∅nsted-Lowry acid has the strongest conjugate base?
A) HBr
B) HClO4
C) HF
D) HI
20) What is the strongest Br∅nsted-Lowry acid in the chemical reaction shown below?
2 HNO3(aq) + Ba(OH)2(aq) → Ba(NO3)2(aq) + 2 H2O(l)
A) HNO3
B) Ba(OH)2
C) Ba(NO3)2
D) H2O
21) From the following chemical reactions determine the relative Br∅nsted-Lowry acid strengths
(strongest to weakest).
HCl(aq) + H2O(l) → H3O+(aq) + Cl–(aq)
HCN(aq) + H2O(l) ⇌ H3O+(aq) + CN–(aq)
A) HCl > HCN > H3O+
B) HCl > H3O+ > HCN
C) H3O+ > HCl > HCN
D) HCN > H3O+ > HCl
22) From the following chemical reactions determine the relative Br∅nsted-Lowry acid strengths
(strongest to weakest).
HClO4(aq) + H2O(l) → H3O+(aq) + ClO4–(aq)
HNO2(aq) + H2O(l) ⇌ H3O+(aq) + NO2–(aq)
A) HClO4 > H3O+ > HNO2
B) HClO4 > HNO2 > H3O+
C) H3O+ > HClO4 > HNO2
D) H3O+ > HNO2 > HClO4
23) From the following chemical reactions determine the relative Br∅nsted-Lowry acid strengths
(strongest to weakest).
HClO4(sol) + CH3COOH(l) → CH3C2(OH)2+(sol) + ClO4–(aq)
H2SO4(sol) + CH3COOH(l) ⇌ CH3C(OH)2+(sol) + HSO4–(sol)
A) HClO4 > H2SO4 > CH3COOH
B) HClO4 > H2SO4 > CH3C(OH)2+
C) HClO4 > CH3COOH > H2SO4
D) HClO4 > CH3C(OH)2+ > H2SO4
24) From the following chemical reactions determine the relative Br∅nsted-Lowry base strengths
(strongest to weakest).
HNO3(aq) + H2O(l) → H3O+(aq) + NO3–(aq)
HF(aq) + H2O(l) ⇌ H3O+(aq) + F–(aq)
A) HNO3 > H3O+ > HF
B) NO3– > H2O > F–
C) F– > H2O > NO3–
D) F– > NO3– > H2O
25) From the following chemical reactions determine the relative Br∅nsted-Lowry base strengths
(strongest to weakest).
2 NaH(s) + H2O(l) → 2 NaOH + H2(g)
NH3(aq) + H2O(l) ⇌ NH4+(aq) + OH–(aq)
A) H– > OH– > NH3
B) H– > NH3 > OH–
C) OH–> H– > NH3
D) OH– > NH3 > H–
26) The equilibrium constant, K, for the reaction shown below has a value 1.8 × 10–5. In this reaction
which is the strongest acid and which is the strongest base?
CH3CO2H(aq) + H2O(l) ⇌ H3O+(aq) + CH3CO2–(aq)
A) CH3CO2H and CH3CO2–
B) CH3CO2H and H2O
C) H3O+ and H2O
D) H3O+ and CH3CO2–
The following pictures represent aqueous solutions of binary acids of the type HA where the water
molecules have been omitted for clarity.
27) Determine the strongest acid of the set.
A) A
B) B
C) C
D) D
28) Arrange the acids in order of increasing acid strength.
A) D < C < A < B
B) D < C < B < A
C) D < B < A < C
D) D < A < C < B
29) Using the conjugate acid-base pairs listed below, complete the following equation with the pair that
gives an equilibrium constant Kc > 1.
_____ + HSO3– ⇌ _____ + H2SO3
A) CH3CO2H/ CH3CO2–
B) HCO2H/ HCO2–
C) HNO2/NO2–
D) HNO3/NO3–
30) Using the conjugate acid-base pairs listed below, complete the following equation with the pair that
gives an equilibrium constant Kc > 1.
_____ + H2CO3 ⇌ _____ + HCO3–
A) HF/F–
B) HCl/Cl–
C) HOCl/OCl–
D) HSO42-/SO42-
31) What is the geometric shape of the hydrated proton; that is, the hydronium ion H3O+?
A) angular
B) pyramidal
C) trigonal planar
D) tetrahedral
32) Which is not a hydrate of a proton?
A) H3O+
B) H9O4+
C) H25O11+
D) H43O21+
33) An acidic solution at 25°C has
A) [H3O+] > [OH–] > 1 × 10-7 M.
B) [H3O+] > 1 × 10-7 M > [OH–].
C) [H3O+] = [OH–] > 1 × 10-7 M.
D) [H3O+] < 1 × 10-7 M > [OH–].
34) At 50°C the value of Kw is 5.5 × 10-14. A basic solution at 50°C has
A) [H3O+] < [OH–] < 2 × 10-7 M.
B) [H3O+] < 2 × 10-7 M < [OH–].
C) [H3O+] = [OH–] < 2 × 10-7 M.
D) [H3O+] > 2 × 10-7 M < [OH–].
35) Calculate the hydronium ion concentration in an aqueous solution that contains 2.50 × 10-4 M in
hydroxide ion.
A) 4.00 × 10-9 M
B) 4.00 × 10-10 M
C) 4.00 × 10-11 M
D) 5.00 × 10-11 M
36) Calculate the hydroxide ion concentration in an aqueous solution that contains 3.50 × 10-3 M in
hydronium ion.
A) 2.86 × 10-4 M
B) 2.86 × 10-11 M
C) 2.86 × 10-12 M
D) 3.50 × 10-12 M
37) A solution with a hydrogen ion concentration of 3.25 × 10-2 M is ________ and has a hydroxide
concentration of ________.
A) acidic, 3.08 × 10-12 M
B) acidic, 3.08 × 10-13 M
C) basic, 3.08 × 10-12 M
D) basic, 3.08 × 10-13 M
38) A solution with a hydroxide ion concentration of 4.15 × 10-4 M is ________ and has a hydrogen ion
concentration of ________.
A) acidic, 2.41 × 10-10 M
B) acidic, 2.41 × 10-11 M
C) basic, 2.41 × 10-10 M
D) basic, 2.41 × 10-11 M
39) If the ionization constant of water, Kw, at 40°C is 2.92 × 10-14, then what is the hydronium ion
concentration for a neutral solution?
A) [H3O+] < 1.00 × 10-7 M
B) [H3O+] > 1.71 × 10-7 M
C) [H3O+] = 1.71 × 10-7 M
D) [H3O+] < 1.71 × 10-7 M
10
40) Normal rainfall has a concentration of OH– that is 3.98 × 10-9. The concentration of H3O+ in
normal rainfall is
A) greater than 3.98 × 10-9, and the rain is acidic.
B) greater than 3.98 × 10-9, and the rain is basic.
C) less than 3.98 × 10-9, and the rain is acidic.
D) less than 3.98 × 10-9, and the rain is basic.
41) Human tears have a concentration of H3O+ that is 3.16 × 10-8. The concentration of OH– in human
tears is
A) greater than 3.16 × 10-7 and tears are acidic.
B) greater than 3.16 ×10-7 and tears are basic.
C) less than 3.16 × 10-7 and tears are acidic.
D) less than 3.16 × 10-7 and tears are basic.
42) An acidic solution at 25°C will have a hydronium ion concentration ________ and a pH value
________.
A) [H3O+] > 1 × 10-7 M, pH > 7.00
B) [H3O+] > 1 × 10-7 M, pH < 7.00
C) [H3O+] < 1 × 10-7 M, pH > 7.00
D) [H3O+] < 1 × 10-7 M, pH < 7.00
43) If the ionization constant of water, Kw, at 40°C is 2.92 × 10-14, then what is the hydronium ion
concentration and pH for an acidic solution?
A) [H3O+] > 1.71 × 10-7 M and pH > 6.77
B) [H3O+] > 1.71 × 10-7 M and pH < 6.77
C) [H3O+] < 1.71 × 10-7 M and pH > 6.77
D) [H3O+] < 1.71 × 10-7 M and pH < 6.77
44) Calculate the pH for an aqueous solution of acetic acid that contains 2.15 × 10-3 M hydronium ion.
A) 4.65 × 10-12
B) 2.15 × 10-3
C) 2.67
D) 11.33
45) Calculate the pH for an aqueous solution of pyridine that contains 2.15 × 10-4 M hydroxide ion.
A) 4.65 × 10-11
B) 2.15 × 10-4
C) 3.67
D) 10.33
46) What is the hydroxide ion concentration and the pH for a hydrochloric acid solution that has a
hydronium ion concentration of 1.50 × 10-4 M?
A) 6.67 × 10-10 M, 4.82
B) 6.67 × 10-10 M, 9.18
C) 6.67 × 10-11 M, 3.82
D) 6.67 × 10-11 M, 10.18
47) What is the hydronium ion concentration and the pH for an aqueous solution of NH3 that has a
hydroxide ion concentration of 2.25 × 10-3 M?
A) 4.44 × 10-11 M, 3.65
B) 4.44 × 10-11 M, 10.35
C) 4.44 × 10-12 M, 2.65
D) 4.44 × 10-12 M, 11.35
48) What is the hydronium ion concentration of an acid rain sample that has a pH of 3.15?
A) 1.41 × 10-11 M
B) 7.08 × 10-4 M
C) 3.15 M
D) 10.85 M
49) What is the hydroxide ion concentration of a lye solution that has a pH of 11.20?
A) 6.31 × 10-12 M
B) 1.58 × 10-3 M
C) 2.80 M
D) 11.20 M
50) What statement is most consistent for an acid with a pH = 3?
A) one one-hundredth as strong as an acid with a pH of 5
B) half a strong as an acid with a pH = 5
C) twice as strong as an acid with a pH of 5
D) one hundred times as strong as an acid with a pH = 5
51) At 25°C, the pH of a vinegar solution is 2.60. What are the values of [H3O+] and [OH–] in the
solution?
A) 3.99 × 10-12 M, 2.51 × 10-3 M
B) 2.51 × 10-3 M, 3.98 × 10-12 M
C) 2.51 × 10-3 M, 11.40 M
D) 2.60 M, 11.40 M
52) What is the approximate pH of a solution X that gives the following responses with the indicators
shown?
Indicators
HIn In–
pH range
Solution X
methyl orange
red-yellow
3.2-4.4
yellow
methyl red
red-yellow
4.8-6.0
yellow
bromothymol blue
yellow-blue
6.0-7.6
green
phenolphthalein
colorless-pink
8.2-10.0
colorless
A) 3.2 – 4.4
B) 4.8 – 6.0
C) 6.0 – 7.6
D) 8.2 – 10.0
53) What is the approximate pH of a solution X that gives the following responses with the indicators
shown?
Indicators
HIn In–
pH range
Solution X
methyl orange
red-yellow
3.2-4.4
yellow
methyl red
red-yellow
4.8-6.0
orange
bromothymol blue
yellow-blue
6.0-7.6
yellow
phenolphthalein
colorless-pink
8.2-10.0
colorless
A) 3.2 – 4.4
B) 4.8 – 6.0
C) 6.0 – 7.6
D) 8.2 – 10.0
54) What is the approximate pH of a solution X that gives the following responses with the indicators
shown?
Indicators
HIn In–
pH range
Solution X
methyl orange
red-yellow
3.2-4.4
yellow
methyl red
red-yellow
4.8-6.0
yellow
bromothymol blue
yellow-blue
6.0-7.6
blue
phenolphthalein
colorless-pink
8.2-10.0
pink
A) 4.8 – 6.0
B) 6.0 – 7.6
C) 7.6 – 8.2
D) > 8.2
55) What is the pH of a 0.020 M HClO4 solution?
A) 0.020
B) 0.040
C) 1.70
D) 12.30
56) What is the pH of a 0.020 M RbOH solution?
A) 0.020
B) 0.040
C) 1.70
D) 12.30
57) What is the pH of a 0.020 M Ba(OH)2 solution?
A) 1.40
B) 1.70
C) 12.30
D) 12.60
58) What is the pH of a solution prepared by dissolving 0.15 gram of solid CaO (lime) in enough water
to make 2.00 L of aqueous Ca(OH)2 (limewater)?
CaO(s) + H2O(l) → Ca2+(aq) + 2 OH–(aq)
A) 2.57
B) 2.87
C) 11.13
D) 11.43
59) What is the pH of a solution prepared by diluting 25.00 mL of 0.10 M HCl with enough water to
produce a total volume of 100.00 mL?
A) 1.00
B) 1.60
C) 2.00
D) 3.20
60) What is the pH of a solution prepared by diluting 25.00 mL of 0.020 M Ba(OH)2 with enough water
to produce a total volume of 250.00 mL?
A) 2.40
B) 2.70
C) 11.30
D) 11.60
61) What is the pH of a solution made by mixing 100.00 mL of 0.20 M HCl with 50.00 mL of 0.10 M
HCl? Assume that the volumes are additive.
A) 0.15
B) 0.52
C) 0.78
D) 1.70
62) What is the pH of a solution made by mixing 100.0 mL of 0.10 M HNO3, 50.0 mL of 0.20 M HCl,
and 100.0 mL of water? Assume that the volumes are additive.
A) 0.30
B) 0.82
C) 1.00
D) 1.10
63) What is the pH of a solution prepared by mixing 100.00 mL of 0.020 M Ca(OH)2 with 50.00 mL of
0.100 M NaOH? Assume that the volumes are additive.
A) 12.67
B) 12.78
C) 12.95
D) 13.25
64) What is the equilibrium constant expression (Ka) for the acid dissociation of hydrocyanic acid
HCN? The equation of interest is
HCN(aq) + H2O(l) ⇌ H3O+(aq) + CN–(aq).
A) Ka = ([H3O+][CN–])/([HCN][H2O])
B) Ka = ([H3O+][CN–])/([HCN])
C) Ka = ([HCN][H2O])/([H3O+][CN–])
D) Ka = ([HCN])/([H3O+][CN–])
65) What is the equilibrium constant expression (Ka) for the acid dissociation of nitrous acid HNO2?
The equation of interest is
HNO2(aq) + H2O(l) ⇌ H3O+(aq) + NO2–(aq).
A) Ka = ([H3O+][NO2–])/([HNO2][H2O])
B) Ka = ([H3O+][NO2–])/([HNO2])
C) Ka = ([HNO2][H2O])/([H3O+][NO2–])
D) Ka = ([HNO2])/([H3O+][NO2–])
66) Determine the acid dissociation constant for a 0.10 M acetic acid solution that has a pH of 2.87.
Acetic acid is a weak monoprotic acid and the equilibrium equation of interest is
CH3COOH(aq) + H2O(l) ⇌H3O+(aq) + CH3CO23–(aq)
A) 1.3 × 10-2
B) 1.3 × 10-3
C) 1.8 × 10-5
D) 1.8 × 10-6
67) Determine the acid dissociation constant for a 0.010 M nitrous acid solution that has a pH of 2.70.
Nitrous acid is a weak monoprotic acid and the equilibrium equation of interest is
HNO2(aq) + H2O(l) ⇌ H3O+(aq) + NO2–(aq).
A) 8.0 × 10-3
B) 2.0 × 10-3
C) 5.0 × 10-4
D) 4.0 × 10-4
68) Determine the acid dissociation constant for a 0.020 M formic acid solution that has a pH of 2.74.
Formic acid is a weak monoprotic acid and the equilibrium equation of interest is
HCOOH(aq) + H2O(l) ⇌ H3O+(aq) + HCO2–(aq).
A) 1.8 × 10-3
B) 1.8 × 10-4
C) 3.6 × 10-4
D) 3.6 × 10-5
69) The pH of 0.255 M HCN is 4.95. What is the value of Ka for hydrocyanic acid?
A) 1.3 × 10-10
B) 4.9 × 10-10
C) 1.1 × 10-5
D) 4.4 × 10-5
70) The pH of 0.150 M CH3CO2H, acetic acid, is 2.78. What is the value of Ka for acetic acid?
A) 2.8 × 10-6
B) 1.9 × 10-5
C) 1.7 × 10-3
D) 1.1 × 10-2
71) What is the strongest monoprotic acid of the following set if all the acids are at 0.100 M
concentration?
A) hydrofluoric acid with Ka = 3.5 × 10-4
B) benzoic acid with Ka = 6.5 × 10-5
C) acetic acid with Ka = 1.8 × 10-5
D) hypochlorous acid with Ka = 3.5 × 10-8
72) What is the hydronium ion concentration of a 0.100 M acetic acid solution with a Ka = 1.8 × 10-5?
The equation for the dissociation of acetic acid is:
CH3CO2H(aq) + H2O(l) ⇌ H3O+(aq) + CH3CO2–(aq).
A) 1.3 × 10-2 M
B) 4.2 × 10-2 M
C) 1.3 × 10-3 M
D) 4.2 × 10-3 M
73) What is the hydronium ion concentration of a 0.100 M hypochlorous acid solution with
Ka = 3.5 × 10-8? The equation for the dissociation of hypochlorous acid is:
HOCl(aq) + H2O(l) ⇌ H3O+(aq) + OCl–(aq).
A) 1.9 × 10-4
B) 5.9 × 10-4
C) 1.9 × 10-5
D) 5.9 × 10-5
74) Para-Aminobenzoic acid (PABA), p-H2NC6H4(COOH), is used in some sunscreens and hair
conditioning products. Calculate the pH of an aqueous solution with [PABA] = 0.030 M and
Ka = 2.2 × 10-5.
A) 1.52
B) 3.09
C) 4.66
D) 6.18
75) A tablet containing 500.0 mg of aspirin (acetylsalicylic acid or HC9H7O4) was dissolved in enough
water to make 100 mL of solution. Given that Ka = 3.0 × 10–4 for aspirin, what is the pH of the
solution?
A) 1.57
B) 2.54
C) 3.52
D) 5.08
76) Benzoic acid (C6H5CO2H = HBz) solutions are sometimes used in experiments to determine the
molarity of a basic solution of unknown concentration. What is the pH of a 0.100 M solution of benzoic
acid if Ka = 6.5 × 10–5 and the equilibrium equation of interest is
HBz(aq) + H2O(l) ⇌ H3O+ + Bz–(aq)?
A) 1.00
B) 2.59
C) 4.19
D) 5.19
77) Potassium hydrogen phthalate (molar mass = 204.2 g/mol) is one of the most commonly used acids
for standardizing solutions containing bases. KHP is a monoprotic weak acid with Ka = 3.91 × 10–6.
Calculate the pH of the solution that results when 0.40 g of KHP is dissolved in enough water to produce
25.0 mL of solution.
A) 2.10
B) 3.26
C) 4.30
D) 5.41
19
78) Vinegar is a 5.0% solution by weight of acetic acid (CH3CO2H) in water. Given that
Ka = 1.8 × 10–5 for acetic acid and assuming the density of vinegar to be 1.00 g/cm3, what is the pH of
this vinegar solution?
A) 2.00
B) 2.41
C) 2.87
D) 4.74
79) Vinegar is a 5.0% solution by weight of acetic acid (CH3CO2H) in water. Given that the pH for
acetic acid is 2.41, the Ka = 1.8 × 10–5 and assuming the density of vinegar to be 1.00 g/cm3, what is
the percent dissociation of acetic acid in vinegar?
A) 0.47%
B) 1.5%
C) 4.0%
D) 5.0%
80) What is the percent dissociation of a benzoic acid solution with pH = 2.59? The acid dissociation
constant for this monoprotic acid is 6.5 × 10–5.
A) 0.50%
B) 1.5%
C) 2.5%
D) 3.5%
81) The percent dissociation of acetic acid changes as the concentration of the acid decreases. A 100–
fold decrease in acetic acid concentration results in a ________ fold ________ in the percent
dissociation.
A) 10, increase
B) 10, decrease
C) 100, increase
D) 100, decrease
82) Which of the following are weak diprotic acids?
A) carbonic acid – H2CO3, hydrosulfuric acid – H2S, acetic acid – CH3CO2H
B) formic acid – HCO2H, acetic acid – CH3CO2H, benzoic acid – C6H5CO2H
C) carbonic acid – H2CO3, oxalic acid – H2C2O4, sulfurous acid – H2SO3
D) hydrocyanic acid – HCN, sulfuric acid – H2SO4, phosphoric acid – H3PO4
83) What is the second stepwise equilibrium constant expression for phosphoric acid H3PO4?
A) Ka2 = ([H3O+][H2PO4–])/([H3PO4])
B) Ka2 = ([H3O+]2[HPO42-])/([H3PO4])
C) Ka2 = ([H3O+]3[PO43-])/([H3PO4])
D) Ka2 = ([H3O+][HPO42-])/([H2PO4–])
84) Calculate the pH of a 0.020 M carbonic acid solution, H2CO3(aq), that has the stepwise dissociation
constants Ka1 = 4.3 × 10-7 and Ka2 = 5.6 × 10-11.
A) 1.70
B) 4.03
C) 6.37
D) 10.25
85) Calculate the pH of a 0.20 M H2SO3 solution that has the stepwise dissociation constants
Ka1 = 1.5 × 10-2 and Ka2 = 6.3 × 10-8.
A) 1.26
B) 1.32
C) 1.82
D) 2.52
86) Calculate the concentration of bicarbonate ion, HCO3–, in a 0.010 M H2CO3 solution that has the
stepwise dissociation constants Ka1 = 4.3 × 10-7 and Ka2 = 5.6 × 10-11.
A) 6.6 × 10-5 M
B) 4.3 × 10-7 M
C) 4.3 × 10-9 M
D) 5.6 × 10-11 M
87) What is the pH of a 0.10 M H2Se solution that has the stepwise dissociation constants
Ka1 = 1.3 × 10-4 and Ka2 = 1.0 × 10-11?
A) 2.44
B) 3.89
C) 4.89
D) 5.50
88) What is the selenide ion concentration [Se2-] for a 0.100 M H2Se solution that has the stepwise