21
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
89) Which of the following can be classified as a weak base?
A) CH3NH2
B) NH2OH
C) Both CH3NH2 and NH2OH
D) Neither CH3NH2 nor NH2OH
90) What is the pH of a 0.100 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) 1.87
B) 2.87
C) 11.13
D) 12.13
91) What is the pH of a 0.30 M pyridine solution that has a 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
92) 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 3.90 g of aniline in enough
water to make 100 mL of solution.
A) 4.87
B) 9.13
C) 9.74
D) 10.74
93) Determine the ammonia concentration of an aqueous solution that has a pH of 11.50. The equation
for the dissociation of NH3 (Kb = 1.8 × 10-5) is
NH3(aq) + H2O(l) ⇌ NH4+(aq) + OH–(aq).
A) 2.5 M
B) 0.55 M
C) 5.7 × 10-3 M
D) 3.2 × 10-3 M
94) How many grams of pyridine are there in 100 mL of an aqueous solution that has a pH of 9.00? The
Kb for pyridine is 1.9 × 10-9 and the equation of interest is
C5H5N(aq) + H2O(l) ⇌ C5H5NH+(aq) + OH–(aq).
A) 0.053 g
B) 0.42 g
C) 0.79 g
D) 7.9 g
95) What is the relationship between Ka and Kb at 25°C for a conjugate acid base pair?
A) Ka × Kb = 1 × 10-14
B) Ka/Kb = 1 × 10-14
C) Kb/Ka = 1 × 10-14
D) Ka + Kb = 1 × 10-14
96) Ammonia NH3, has a base dissociation constant of 1.8 × 10-5. What is the conjugate acid of
ammonia and what is its acid dissociation constant?
A) NH4+, 1.9 × 109
B) NH4+, 1.8 × 10-5
C) NH4+, 5.6 × 10-10
D) NH2–, 5.6 × 10-10
97) Methylamine CH3NH2, has a base dissociation constant of 3.7 × 10-4. What is the conjugate acid of
methylamine and what is its acid dissociation constant?
A) CH3NH3+, 2.7 × 103
B) CH3NH3+, 3.7 × 10-4
C) CH3NH3+, 2.7 × 10-11
D) CH3NH2–, 2.7 × 10–11
98) Acetic acid CH3COOH, has an acid dissociation constant of 1.8 × 10-5. What is the conjugate base
of acetic acid and what is its base dissociation constant?
A) CH3C(OH)2+, 5.6 × 104
B) CH3C(OH)2+, 5.6 × 10-10
C) CH3COOH, 5.6 × 10-10
D) CH3CO2–, 5.6 × 10–10
99) Dihydrogen phosphate H2PO4–, has an acid dissociation constant of 6.2 × 10-7. What is the
conjugate base of H2PO4– and what is its base dissociation constant?
A) H3PO4, 1.6 × 106
B) H3PO4, 1.6 × 10-8
C) HPO42-, 1.6 × 106
D) HPO42-, 1.6 × 10-8
100) Which of the following salts are acidic?
A) LiCl, NaCl, KCl
B) NH4Cl, CuCl2, AlCl3
C) NaCH3CO2, KCH3CO2, RbCH3CO2
D) NaCl, NH4Cl, Na2CO3
101) Which one of the following salts, when dissolved in water, produces the solution with the highest
pH?
A) NaHSO4
B) LiClO4
C) MgO
D) CH3NH3I
102) 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.
103) Arrange the following 0.10 M aqueous solutions in order of increasing pH:
NaOH, HBr, NaCH3CO2, KBr, NH4Br.
A) HBr, KBr, NH4Br, NaCH3CO2, NaOH
B) NaOH, NaCH3CO2, NH4Br, KBr, HBr
C) NaOH, NaCH3CO2, KBr, NH4Br, HBr
D) HBr, NH4Br, KBr, NaCH3CO2, NaOH
104) Which one of the following salts, when dissolved in water, produces the solution with the highest
pH?
A) KI
B) KBr
C) KCl
D) KF
105) Which one of the following salts, when dissolved in water, produces the solution with a pH closest
to 7.00?
A) NH4Cl
B) BaO
C) NaHSO4
D) RbI
106) Calculate the pH of a 0.100 M NaCH3CO2 solution. Ka for acetic acid, CH3CO2H, is 1.8 × 10-5.
A) 2.87
B) 5.13
C) 8.87
D) 11.13
25
107) Calculate the pH of a of 0.100 M KBrO solution. Ka for hypobromous acid, HBrO, is 2.0 × 10-9.
A) 3.15
B) 4.85
C) 9.15
D) 10.85
108) Calculate the pH of a 0.100 M CH3NH3Cl solution. Kb for methylamine, CH3NH2, is 3.7 × 10-4.
A) 2.22
B) 5.78
C) 8.22
D) 11.78
109) Equal volumes of 0.10 M NH3 (Kb = 1.8 × 10-5) and 0.10 M HCN (Ka = 4.9 × 10-10) are mixed
together. Will the resulting solution be acidic, basic, or neutral?
A) acidic
B) basic
C) neutral
D) insufficient information to solve
110) Which one of the following salts, when dissolved in water, produces the solution with the lowest
pH?
A) NaCl
B) NH4Cl
C) MgCl2
D) AlCl3
111) What is the identity of M in the hydrate M(H2O)6n+ that has the 0.10 M solution with the lowest
pH?
A) Li+
B) Na+
C) Mg2+
D) Al3+
112) What is the identity of M in the hydrate M(H2O)6n+ that has the 0.10 M solution with the highest
pH?
A) Li+
B) Na+
C) Mg2+
D) Al3+
113) What is the strongest acid among the following?
A) HF
B) HCl
C) HBr
D) HI
114) What is the strongest acid among the following?
A) H2O
B) H2S
C) H2Se
D) H2Te
115) What is the strongest acid among the following?
A) HF
B) HCl
C) H2O
D) H2S
116) What is the weakest acid among the following?
A) SiH4
B) PH3
C) H2S
D) HCl
117) Which acid of the following set has the strongest conjugate base?
A) CH4
B) NH3
C) H2O
D) HF
118) What is the strongest base among the following?
A) ClO–
B) ClO2–
C) ClO3–
D) ClO4–
119) What is the strongest acid among the following?
A) H2SO3
B) H2SO4
C) H2SeO3
D) H2SeO4
120) What is the strongest acid of the following?
A) HOI
B) HOBr
C) HOCl
D) All are equivalent.
121) What is the strongest acid among the following?
A) HIO
B) HIO2
C) HIO3
D) HIO4
122) What is the strongest acid among the following?
A) CH3CO2H
B) ClCH2CO2H
C) Cl2CHCO2H
D) Cl3CCO2H
123) Identify the Lewis acid that acts as a reactant in the following reaction.
Fe(H2O)63+(aq) + 6 CN–(aq) → Fe(CN)63-(aq) + 6 H2O(l)
A) Fe3+
B) H2O
C) CN–
D) Fe(H2O)63+
124) Identify the Lewis acid that acts as a reactant in the following reaction.
Co(H2O)63+(aq) + 6 NH3(aq) → Co(NH3)63+(aq) + 6 H2O(l)
A) Co(H2O)63+
B) Co3+
C) NH3
D) H2O
125) For Cu2+ and CO2, which will behave as a Lewis acid toward OH– in water?
A) only Cu2+
B) only CO2
C) Cu2+ and CO2
D) neither Cu2+ nor CO2
126) Which one of the following is not considered to be a Lewis base?
A) H2O
B) NH3
C) NH4+
D) Cl–
127) Which one of the following is least able to behave as a Lewis base?
A) CH3NH2
B) (CH3)2NH
C) (CH3)3N
D) (CH3)3NH+
128) The compound BF3 can be described as a(n) ________.
A) Arrhenius acid
B) Br∅nsted-Lowry acid
C) Lewis acid
D) Lewis base
129) Identify the set of Lewis acids.
A) BH3, BF3, Cu2+, CO2
B) Cl–, OH–, NH3, H2O
C) H3PO4, H2PO4–, HPO42-, PO43-
D) CH3–, NH2–, OH–, F–
130) Which one of the following is expected to be the strongest Lewis acid?
A) Fe
B) Fe+
C) Fe2+
D) Fe3+
In the following reaction the unshaded spheres represent H atoms.
131) Identify the Br∅nsted-Lowry acids.
A) (1) and (3)
B) (1) and (4)
C) (2) and (3)
D) (2) and (4)
132) Identify the Br∅nsted-Lowry bases.
A) (1) and (3)
B) (1) and (4)
C) (2) and (3)
D) (2) and (4)
In the following reaction the unshaded spheres represent H atoms.
133) Identify the Br∅nsted-Lowry acids.
A) (1) and (3)
B) (1) and (4)
C) (2) and (3)
D) (2) and (4)
134) Identify the Br∅nsted-Lowry bases.
A) (1) and (3)
B) (1) and (4)
C) (2) and (3)
D) (2) and (4)
In the following reaction the unshaded spheres represent H atoms.
135) Identify the Br∅nsted-Lowry acid/base conjugate pairs.
A) (1)/(2) and (3)/(4)
B) (1)/(3) and (2)/(4)
C) (1)/(4) and (2)/(3)
In the following reaction the unshaded spheres represent H atoms.
136) Identify the Br∅nsted-Lowry acid/base conjugate pairs.
A) (1)/(2) and (3)/(4)
B) (1)/(3) and (2)/(4)
C) (1)/(4) and (2)/(3)
The following pictures represent aqueous solutions of three acids HA (A = X, Y, or Z); water molecules
have been omitted for clarity.
137) Arrange the three acids in order of increasing acid strength.
A) HZ < HY < HX
B) HY < HZ < HX
C) HZ < HX < HY
D) HX < HZ < HY
138) Which acid, if any, is a strong acid?
A) All are strong acids.
B) HX and HZ
C) HY
D) None are strong acids.
139) Which acid has the smallest value of Ka?
A) HX
B) HY
C) HZ
D) All have the same Ka value.
140) Which acid has the lowest percent dissociation?
A) HX
B) HY
C) HZ
D) All have the same percent dissociation.
141) Which acid solution has the lowest pH?
A) HX
B) HY
C) HZ
D) All have the same pH.
142) Which of the above pictures represents a solution of a weak diprotic acid H2A for which
Ka1 >> Ka2? (Water molecules have been omitted for clarity.)
A) picture (a)
B) picture (b)
C) picture (c)
D) picture (d)
143) Which of the above pictures represents a solution of a diprotic acid H2A for which Ka1 = and
Ka2 is exceptionally small. (Water molecules have been omitted for clarity.)
A) picture (a)
B) picture (b)
C) picture (c)
D) picture (d)
The following pictures represent equal volumes of aqueous solutions of three acids HA (A = X, Y, or Z);
water molecules have been omitted for clarity.
144) Arrange the acids in order of increasing acid strength.
A) HZ < HY < HX
B) HY < HZ < HX
C) HZ < HX < HY
D) HX < HZ < HY
145) Arrange the acids in order of increasing value of Ka.
A) Ka(HZ) < Ka(HY) < Ka(HX)
B) Ka(HY) < Ka(HZ) < Ka(HX)
C) Ka(HZ) < Ka(HX) < Ka(HY)
D) Ka(HX) < Ka(HZ) < Ka(HY)
146) Arrange the acids in order of increasing value of percent dissociation.
A) HZ < HY < HX
B) HY < HZ < HX
C) HZ < HX < HY
D) HX < HZ < HY
147) Arrange the acids in order of increasing pH.
A) HZ < HY < HX
B) HY < HZ < HX
C) HZ < HX < HY
D) HX < HZ < HY
148) Arrange the conjugate bases (A– = X–, Y–, or Z–) in order of increasing base strength.
A) Z– < Y– < X–
B) Y– < Z– < X–
C) Z– < X– < Y–
D) X– < Z– < Y–
149) Arrange the conjugate bases (A– = X–, Y–, or Z–) in order of increasing value of Kb.
A) Kb(Z–) < Kb(Y–) < Kb(X–)
B) Kb(Y–) < Kb(Z–) < Kb(X–)
C) Kb(Z–) < Kb(X–) < Kb(Y–)
D) Kb(X–) < Kb(Z–) < Kb(Y–)
150) The following pictures represent solutions of three salts NaA (A– = X–, Y–, or Z–); water molecules
and Na+ ions have been omitted for clarity. Arrange the three A– ions in order of decreasing base
strength.
A) X– > Y– > Z–
B) X– > Z– > Y–
C) Y– > Z– > X–
D) Z– > Y– > XZ–