The following pictures represent solutions of three salts MA; water molecules have been omitted for
clarity. Dotted spheres represent Ay– ions; gray spheres represent Mx+ ions; black spheres represent
oxygen atoms; and unshaded spheres represent hydrogen atoms.
151) Which picture represents an acidic salt?
A) (1)
B) (2)
C) (3)
D) None of these
152) Which picture represents a neutral salt?
A) (1)
B) (2)
C) (3)
D) None of these
153) Which picture represents a basic salt?
A) (1)
B) (2)
C) (3)
D) None of these
154) Of the elements indicated on the periodic table shown above, which forms the strongest binary
acid, H2X or HX, where X = A, B, C, or D?
A) A
B) B
C) C
D) D
155) Of the elements indicated on the periodic table shown above, which forms the weakest binary acid,
H2X or HX, where X = A, B, C, or D?
A) A
B) B
C) C
D) D
156) Of the elements indicated on the periodic table shown above, which forms the strongest oxoacid
acid with the formula H2XO3 or HXO3, where X = A, B, C, or D?
A) A
B) B
C) C
D) D
157) Of the elements indicated on the periodic table shown above, which forms the weakest oxoacid
acid with the formula H2XO3 or HXO3, where X = A, B, C, or D?
A) A
B) B
C) C
D) D
39
158) SO3 reacts with H2O to form H2SO4. Which picture below correctly represents the curved arrow
notation for the initial Lewis acid-Lewis base interaction in this reaction; what is the Lewis acid and the
Lewis base?
A) Picture (1) is correct; H2O is the Lewis acid and SO3 is the Lewis base.
B) Picture (1) is correct; SO3 is the Lewis acid and H2O is the Lewis base.
C) Picture (2) is correct; H2O is the Lewis acid and SO3 is the Lewis base.
D) Picture (2) is correct; SO3 is the Lewis acid and H2O is the Lewis base.
159) CO2 reacts with H2O to form HCO3– and H+. Which picture below correctly represents the curved
arrow notation for the initial Lewis acid-Lewis base interaction in this reaction; what is the Lewis acid
and the Lewis base?
(1) (2)
A) Picture (1) is correct; H2O is the Lewis acid and CO2 is the Lewis base.
B) Picture (1) is correct; CO2 is the Lewis acid and H2O is the Lewis base.
C) Picture (2) is correct; H2O is the Lewis acid and CO2 is the Lewis base.
D) Picture (2) is correct; CO2 is the Lewis acid and H2O is the Lewis base.
160) BF3 and NH3 undergo a Lewis acid-base reaction forming an adduct. Which picture below
correctly represents the curved arrow notation for the initial Lewis acid-Lewis base interaction in this
reaction; what is the Lewis acid and the Lewis base?
A) Picture (1) is correct; NH3 is the Lewis acid and BF3 is the Lewis base.
B) Picture (2) is correct; BF3 is the Lewis acid and NH3 is the Lewis base.
C) Picture (3) is correct; NH3 is the Lewis acid and BF3 is the Lewis base.
D) Picture (4) is correct; BF3 is the Lewis acid and NH3 is the Lewis base.
14.2 Algorithmic Questions
1) When dissolved in water, which compound is generally considered to be an Arrhenius acid?
A) H NO2
B) KOH
C) Li F
D) CH3OH
2) Which Br∅nsted-Lowry acid is not considered to be a strong acid in water?
A) H I
B) H Br
C) H2S O3
D) H NO3
3) Calculate the hydronium ion concentration in an aqueous solution that contains 2.50 × 10– 6 M in
hydroxide ion.
A) 4.00 × 10– 7 M
B) 4.00 × 10– 8 M
C) 4.00 × 10– 9 M
D) 5.00 × 10– 9 M
4) Calculate the hydroxide ion concentration in an aqueous solution that contains 3.50 × 10– 4 M in
hydronium ion.
A) 2.86 × 10– 3 M
B) 2.86 × 10– 10 M
C) 2.86 × 10– 11 M
D) 3.50 × 10– 11 M
5) A solution with a hydrogen ion concentration of 3.25 × 10– 6 M is ________ and has a hydroxide ion
concentration of ________.
A) acidic, 3.08 × 10– 8 M
B) acidic, 3.08 × 10– 9 M
C) basic, 3.08 × 10– 8 M
D) basic, 3.08 × 10– 9 M
6) A solution with a hydroxide ion concentration of 4.15 × 10– 6 M is ________ and has a hydrogen ion
concentration of ________.
A) acidic, 2.41 × 10– 8 M
B) acidic, 2.41 × 10– 9 M
C) basic, 2.41 × 10– 8 M
D) basic, 2.41 × 10– 9 M
7) Calculate the pH for an aqueous solution of acetic acid that contains 2.15 × 10-3 M hydronium ion.
A) 4.65 × 10-12 M
B) 2.15 × 10-3 M
C) 2. 67
D) 11. 33
8) 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
9) What is the hydroxide ion concentration and the pH for a hydrochloric acid solution that has a
hydronium ion concentration of 1.50 × 10-2 M?
A) 6.67 × 10– 12 M, 2.82
B) 6.67 × 10– 12 M, 11.18
C) 6.67 × 10– 13 M, 1.82
D) 6.67 × 10– 13 M, 12.17
10) What is the hydronium ion concentration and the pH for an aqueous solution of NH3 that has a
hydroxide ion concentration of 2.25 × 10-2 M?
A) 4.44 × 10– 12 M and 2.65
B) 4.44 × 10– 12 M and 11.35
C) 4.44 × 10– 13 M and 1.65
D) 4.44 × 10– 13 M and 12.35
11) What is the hydronium ion concentration of an acid rain sample that has a pH of 3. 45?
A) 2.82 × 10-11 M
B) 3.55 × 10-4 M
C) 3. 45 M
D) 10. 55 M
12) What is the hydroxide ion concentration of a lye solution that has a pH of 9.20?
A) 6.31 × 10– 10 M
B) 1.58 × 10– 5 M
C) 4.80 M
D) 9.20 M
13) What is the pH of a 0. 020 M HClO4 solution?
A) 0. 020
B) 0. 040
C) 1.70
D) 12.30
14) What is the pH of a 0.0 40 M Ba(OH)2 solution?
A) 1.10
B) 1.40
C) 12.60
D) 12.90
15) What is the pH of a solution prepared by dissolving 0. 45 grams 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) 2.10
B) 2.40
C) 11.60
D) 11.90
16) What is the pH of a solution prepared by diluting 20.00 mL of 0.10 M HCl with enough water to
produce a total volume of 100.00 mL?
A) 1.00
B) 1. 70
C) 2.00
D) 3.40
17) What is the pH of a solution prepared by diluting 100.00 mL of 0.020 M Ba(OH)2 with enough
water to produce a total volume of 250.00 mL?
A) 1.80
B) 2. 10
C) 11.90
D) 12.20
18) What is the pH of a solution prepared by mixing 100.00 mL of 0.20 M HCl with 150.00 mL of 0. 10
M HCl? Assume that the volumes are additive.
A) 0. 17
B) 0. 52
C) 0. 85
D) 1.70
19) 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. 300 M NaOH? Assume that the volumes are additive.
A) 13.05
B) 13.10
C) 13.28
D) 13.58
20) What is the hydronium ion concentration of a 0. 500 M acetic acid solution with Ka = 1.8 × 10-5?
The equation for the dissociation of acetic acid is:
CH3CO2H(aq) + H2O(l) ⇌ H3O+(aq) + CH3CO2–(aq).
A) 3.0 × 10-2 M
B) 4.2 × 10-2 M
C) 3.0 × 10-3 M
D) 4.2 × 10-3 M
21) What is the hydronium ion concentration of a 0. 150 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 M
B) 7.2 × 10-4 M
C) 2.8 × 10-5 M
D) 7.2 × 10-5 M
22) 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. 50 g of KHP is dissolved in enough water to
produce 25.0 mL of solution.
A) 2.05
B) 3. 21
C) 4. 40
D) 5.41
23) Calculate the pH of a 0. 080 M carbonic acid solution, H2CO3(aq), that has the stepwise
dissociation constants Ka1 = 4.3 × 10-7 and Ka2 = 5.6 × 10-11.
A) 1.10
B) 3.73
C) 6.37
D) 10.25
24) Calculate the pH of a 0. 60 M H2SO3, solution that has the stepwise dissociation constants
Ka1 = 1.5 × 10-2 and Ka2 = 6.3 × 10-8.
A) 1.02
B) 1.06
C) 1.82
D) 2.04
25) Calculate the concentration of bicarbonate ion, HCO3–, in a 0.0 10 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
26) What is the pH of a 0. 40 M H2Se solution that has the stepwise dissociation constants
Ka1 = 1.3 × 10-4 and Ka2 = 1.0 × 10-11?
A) 2. 14
B) 3.89
C) 4. 28
D) 5. 57
27) What is the selenide ion concentration [Se2-] for a 0. 100 M H2Se solution that has the stepwise
dissociation constants of Ka1 = 1.3 × 10-4 and Ka2 = 1.0 × 10-11?
A) 3.6 × 10-3 M
B) 1.3 × 10-4 M
C) 1.3 × 10-5 M
D) 1.0 × 10-11 M
28) What is the pH of a 0. 200 M NH3 solution that has Kb = 1.8 × 10-5? The equation for the
dissociation of NH3 is
NH3(aq) + H2O(l) ⇌ NH4+(aq) + OH–(aq).
A) 2.02
B) 2. 72
C) 11. 98
D) 11.28
29) What is the pH of a 0.30 M pyridine solution that has Kb = 1.9 × 10-9? The equation for the
dissociation of pyridine is
C5H5N(aq) + H2O(l) ⇌ C5H5NH+(aq) + OH–(aq).
A) 4. 62
B) 8.72
C) 9. 38
D) 10. 38
30) Aniline, (C6H5NH2, Kb = 4.3 × 10-10 at 25°C) is an industrially important amine used in the
making of dyes. Determine the pH of an aniline solution made by dissolving 6.90 g of aniline in enough
water to make 100 mL of solution.
A) 4. 75
B) 9. 25
C) 9. 50
D) 10. 50
31) Determine the ammonia concentration of an aqueous solution that has a pH of 11. 00. The equation
for the dissociation of NH3 (Kb = 1.8 × 10-5) is
NH3(aq) + H2O(l) ⇌ NH4+(aq) + OH–(aq).
A) 3.0 M
B) 0. 056 M
C) 1.8 × 10– 2 M
D) 1.0 × 10-3 M
32) Which one of the following salts, when dissolved in water, produces the solution with the highest
pH?
A) KH CO3
B) CsClO4
C) RaO
D) CH3CH3NH3Cl
33) If an equal number of moles of the weak acid HCN and the strong base KOH are added to water,
is the resulting solution acidic, basic, or neutral?
A) acidic
B) basic
C) neutral
D) There is insufficient information provided to answer this question.
34) Which one of the following salts, when dissolved in water, produces the solution with the highest
pH?
A) RbI
B) RbBr
C) RbCl
D) RbF
35) Which one of the following salts, when dissolved in water, produces the solution with a pH closest
to 7.00?
A) NH4Br
B) Ca O
C) K HSO4
D) Cs I
36) Calculate the pH of a 0.800 M NaCH3CO2 solution. Ka for acetic acid, CH3CO2H, is 1.89 × 10-5.
A) 2. 42
B) 4.68
C) 9.32
D) 11. 58
37) Calculate the pH of a 1.60 M KBrO solution. Ka for hypobromous acid, HBrO, is 2.0 × 10-9.
A) 2.55
B) 4.25
C) 9. 75
D) 11.45
38) Calculate the pH of a 1.60 M CH3NH3Cl solution. Kb for methylamine, CH3NH2, is 3.7 × 10-4.
A) 1.61
B) 5. 18
C) 8. 82
D) 12.39
39) Which one of the following salts, when dissolved in water, produces the solution with the lowest
pH?
A) NaCl
B) KCl
C) MgCl2
D) AlCl3
49
14.3 Short Answer Questions
1) The Br∅nsted-Lowry acids in the chemical equation below are ________ and ________.
HNO2(aq) + H2O(l) ⇌ H3O+(aq) + NO2–(aq)
2) The equilibrium constant for the reaction below has the value Ka = 3.5 × 10-4. In this reaction the
stronger Br∅nsted-Lowry acid is ________ and the weaker Br∅nsted-Lowry acid is ________.
HF(aq) + H2O(l) ⇌ H3O+(aq) + F–(aq)
3) A proton hydrated by four water molecules has the formula ________.
4) The number of waters of hydration in the hydrate proton H7O3+ is ________.
5) An acidic solution with hydronium ion concentration [H+] = 1.60 × 10–3 M has a hydroxide ion
concentration [OH–] = ________.
6) The concentration of H3O+ in human sweat can be as low as 2.5 × 10-6. The concentration of OH– in
the sweat is ________, and this solution is ________ (acidic, basic, neutral).
7) Undersea flora prefer a maximum concentration of OH– of 1.58 × 10-5. The concentration of H3O+
in the seawater is ________, and this solution is ________ (acidic, basic, neutral).
8) At the normal body temperature of 37°C, Kw = 2.42 × 10-14. The H3O+ concentration of normal
blood ranges from 3.5 × 10-8 to 4.5 × 10-8. The OH– concentration of normal blood ranges from
________ to ________, and blood is ________ (acidic, basic, neutral).
50
9) At 50°C the value of Kw is 5.5 × 10–14, and the pH of a neutral solution at 50°C is ________.
10) One way to prepare a solution with a pH of 10.00 is to dissolve ________ grams of CaO in enough
water to make 500 mL of solution.
11) Bromothymol blue indicator changes color from yellow at a pH of 6.0 to blue at a pH of 7.6. Phenol
red indicator changes color from yellow at a pH of 6.8 to red at a pH of 8.4. A sample of pancreatic fluid
having [OH–] = 1.258 × 10-6 would impart a ________ color to bromothymol blue and a ________
color to phenol red.
12) Bromothymol blue indicator changes color from yellow at a pH of 6.0 to blue at a pH of 7.6. Methyl
red indicator changes color from red at a pH of 4.4 to yellow at a pH of 6.2. A sample of saliva having
[H3O+] = 6.310 × 10-7 would impart a ________ color to bromothymol blue and a ________ color to
methyl red.
13) The pH of a 0.025 M KOH solution is ________.
14) The value of Ka for a 0.250 M HCN solution having a pH of 4.956 is ________.
15) In order for the reaction HA + HSO3– ⇌ A– + H2SO3 to have an equilibrium constant Kc < 1, the
Ka of HA must be ________ (greater, less) than the Ka of HSO3–.
16) In order for the reaction A– + H2CO3 ⇌ HA + HCO3– to have an equilibrium constant Kc < 1, the
Ka of HA must be ________ (greater, less) than the Ka of H2CO3.
17) A 1.25 × 10-4 M solution of the anti-inflammatory drug naproxen has a pH = 4.2. The Ka and pKa
of naproxen are ________ and ________.
18) Phenobarbital is an antiepileptic drug with a water solubility of 4.3 × 10-3 M and pKa = 7.4. What is
the pH and percent ionization of 4.3 × 10-3 M phenobarbital?
19) Phenobarbital has a pKa = 7.4. Compared to a 1.0 × 10-3 M solution, 1.0 × 10-4 M phenobarbital
will have a ________ (higher, lower) pH and a ________ (higher, lower) percent ionization.
20) Erythromycin is a basic antimicrobial with pKb = 5.2. A 1.0 × 10-3 M solution of erythromycin has
a pH of and a percent ionization.
21) A 0.050 M solution of hydroxylamine, NH2OH, having Kb = 9.1 × 10–9 has a pH of ________.
22) A 0.10 M KNO2 solution will have a pH ________ seven.
23) The acid strength of an oxoacid having the general formula HnYOm increases as the
electronegativity of Y ________ and as the oxidation number of Y ________.
24) In the aquation reaction Co2+ + 6 H2O → [Co(H2O)6]2+, the Lewis acid is ________ and the
Lewis base is________.
25) In the reaction between NO2 and H2O that produces HNO3, the Lewis acid is ________ and the
Lewis base is ________.