Answer at the bottom of the page
16.1 Multiple-Choice Questions
1) According to the Arrhenius concept, an acid is a substance that __________.
A) is capable of donating one or more H+
B) causes an increase in the concentration of H+ in aqueous solutions
C) can accept a pair of electrons to form a coordinate covalent bond
D) reacts with the solvent to form the cation formed by autoionization of that solvent
E) tastes bitter
2) A BrØnsted-Lowry base is defined as a substance that __________.
A) increases [H+] when placed in H2O
B) decreases [H+] when placed in H2O
C) increases [OH-] when placed in H2O
D) acts as a proton acceptor
E) acts as a proton donor
3) A BrØnsted-Lowry acid is defined as a substance that __________.
A) increases Ka when placed in H2O
B) decreases [H+] when placed in H2O
C) increases [OH-] when placed in H2O
D) acts as a proton acceptor
E) acts as a proton donor
4) Which one of the following is a BrØnsted -Lowry acid?
A) (CH3)3NH+
B) CH3COOH
C) HF
D) HNO2
E) all of the above
5) A substance that is capable of acting as both an acid and as a base is __________.
A) autosomal
B) conjugated
C) amphoteric
D) saturated
E) miscible
6) Which one of the following is a BrØnsted -Lowry base?
A) (CH3)3N
B) CH3COOH
C) HF
D) HNO2
E) none of the above
7) The molar concentration of hydronium ion in pure water at 25°C is __________.
A) 0.00
B) 1.0 × 10-7
C) 1.0 × 10-14
D) 1.00
E) 7.00
8) The molar concentration of hydroxide ion in pure water at 25°C is __________.
A) 1.00
B) 0.00
C) 1.0 ×10-14
D) 1.0 × 10-7
E) 7.00
9) The magnitude of Kw indicates that __________.
A) water autoionizes very slowly
B) water autoionizes very quickly
C) water autoionizes only to a very small extent
D) the autoionization of water is exothermic
10) In basic solution, __________.
A) [H3O+] = [OH-]
B) [H3O+] > [OH-]
C) [H3O+] < [OH-]
D) [H3O+] = 0 M
E) [OH-] > 7.00
11) Which solution below has the highest concentration of hydroxide ions?
A) pH = 3.21
B) pH = 12.6
C) pH = 7.93
D) pH = 9.82
E) pH = 7.00
12) Which solution below has the highest concentration of hydronium ions?
A) pH = 3.21
B) pH = 12.6
C) pH = 7.93
D) pH = 9.82
E) pH = 7.00
13) Which one of the following statements regarding Kw is false?
A) pKw is 14.00 at 25°C
B) The value of Kw is always 1.0 × 10-14.
C) Kw changes with temperature.
D) The value of Kw shows that water is a weak acid.
E) Kw is known as the ion product of water.
14) The hydride ion, H-, is a stronger base than the hydroxide ion, OH-. The product(s) of the reaction of hydride ion with water is/ are __________.
A) H3O+ (aq)
B) OH- (aq) + H2 (g)
C) OH- (aq) + 2H+ (aq)
D) no reaction occurs
E) H2O2 (aq)
15) An aqueous solution contains 0.10 M NaOH. The solution is __________.
A) very dilute
B) highly colored
C) basic
D) neutral
E) acidic
16) Nitric acid is a strong acid. This means that __________.
A) aqueous solutions of HNO3 contain equal concentrations of H+(aq) and OH-(aq)
B) HNO3 does not dissociate at all when it is dissolved in water
C) HNO3 dissociates completely to H+(aq) and NO3-(aq) when it dissolves in water
D) HNO3 produces a gaseous product when it is neutralized
E) HNO3 cannot be neutralized by a weak base
17) Of the following acids, __________ is a strong acid.
A) HNO2
B) H2CO3
C) HBrO3
D) HClO
E) HF
18) Of the following acids, __________ is not a strong acid.
A) HNO2
B) H2SO4
C) HNO3
D) HClO4
E) HCl
19) Of the following, __________ is a weak acid.
A) HF
B) HCl
C) HBr
D) HNO3
E) HClO4
20) Which one of the following is the weakest acid?
A) HF (Ka = 6.8 × 10-4)
B) HClO (Ka = 3.0 × 10-8)
C) HNO2 (Ka = 4.5 × 10-4)
D) HCN (Ka = 4.9 × 10-10)
E) Acetic acid (Ka = 1.8 × 10-5)
21) Of the acids in the table below, __________ is the strongest acid.
A) HOAc
B) HCHO2
C) HClO
D) HF
E) HOAc and HCHO2
22) The Ka of hypochlorous acid (HClO) is 3.0 × 10-8 at 25.0°C. What is the % ionization of hypochlorous acid in a 0.015 M aqueous solution of HClO at 25.0°C?
A) 4.5 × 10-8
B) 14
C) 2.1 × 10-5
D) 0.14
E) 1.4 × 10-3
23) In which of the following aqueous solutions does the weak acid exhibit the highest percentage ionization?
A) 0.01 M HC2H3O2 (Ka = 1.8 × 10-5)
B) 0.01 M HNO2 (Ka = 4.5 × 10-4)
C) 0.01 M HF (Ka = 6.8 × 10-4)
D) 0.01 M HClO (Ka = 3.0 × 10-8)
E) These will all exhibit the same percentage ionization.
24) Classify the following compounds as weak acids (W) or strong acids (S):
benzoic acid nitric acid acetic acid
A) W W W
B) S S S
C) S W W
D) W S S
E) W S W
25) Classify the following compounds as weak acids (W) or strong acids (S):
hydrocyanic acid hydrofluoric acid phenol
A) W W W
B) S S S
C) S W W
D) W S S
E) W S W
26) In which of the following aqueous solutions does the weak acid exhibit the lowest percentage ionization?
A) 0.01 M HC2H3O2 (Ka = 1.8 × 10-5)
B) 0.01 M HNO2 (Ka = 4.5 × 10-4)
C) 0.01 M HF (Ka = 6.8 × 10-4)
D) 0.01 M HClO (Ka = 3.0 × 10-8)
E) These will all exhibit the same percentage ionization.
27) Classify the following compounds as weak acids (W) or strong acids (S):
nitrous acid hydrochloric acid hydrofluoric acid
A) W W W
B) S S S
C) S W W
D) W S S
E) W S W
28) Classify the following compounds as weak acids (W) or strong acids (S):
hypochlorous acid perchloric acid chloric acid
A) W S S
B) S S S
C) S W W
D) W W W
E) W S W
29) Ammonia is a __________.
A) weak acid
B) strong base
C) weak base
D) strong acid
E) salt
30) HA is a weak acid. Which equilibrium corresponds to the equilibrium constant Kb for A-?
A) HA (aq) + H2O (l) H2A+ (aq) + OH- (aq)
B) A- (aq) + H3O+ (aq) HA (aq) + H2O (l)
C) HA (aq) + OH- (aq) H2O (l) + H+ (aq)
D) A- (aq) + H2O (l) HA (aq) + OH- (aq)
E) A- (aq) + OH- (aq) HOA2- (aq)
31) A- is a weak base. Which equilibrium corresponds to the equilibrium constant Ka for HA?
A) HA (aq) + H2O (l) H2A+ (aq) + OH- (aq)
B) A- (aq) + H3O+ (aq) HA (aq) + H2O (l)
C) HA (aq) + H2O (l) H3O+ (aq) + A- (aq)
D) A- (aq) + H2O (l) HA (aq) + OH- (aq)
E) A- (aq) + OH- (aq) HOA2- (aq)
32) Classify the following compounds as weak bases (W) or strong bases (S):
ammonia fluoride ion sodium hydroxide
A) W W S
B) S S S
C) S W W
D) W S S
E) W S W
33) Classify the following compounds as weak bases (W) or strong bases (S):
methylamine carbonate ion potassium hydroxide
A) W W S
B) S S S
C) S W W
D) W S S
E) W S W
34) Using the data in the table, which of the conjugate bases below is the strongest base?
A) OAc-
B) C7H5O2-
C) NO2-
D) F-
E) OAc- and C7H5O2-
35) Using the data in the table, which of the conjugate bases below is the weakest base?
A) OAc-
B) C7H5O2-
C) NO2-
D) F-
E) OAc- and C7H5O2-
36) Using the data in the table, which of the conjugate bases below is the strongest base?
A) OAc-
B) CHO2-
C) ClO-
D) F-
E) OAc- and CHO2-
37) Using the data in the table, which of the conjugate bases below is the weakest base?
A) OAc-
B) CHO2-
C) ClO-
D) F-
E) OAc- and CHO2-
38) Using the data in the table, which of the conjugate acids below is the strongest acid?
A) HClO
B) HCO3-
C) H2S
D) NH3CH3+
E) H2S and HClO
39) Using the data in the table, which of the conjugate acids below is the weakest acid?
A) HClO
B) HCO3-
C) H2S
D) NH3CH3+
E) H2S and HClO
40) Using the data in the table, which of the conjugate acids below is the strongest acid?
A) NH4+
B) C5H5NH+
C) H3NOH+
D) NH3CH3+
E) NH4+ and NH3CH3+
41) Using the data in the table, which of the conjugate acids below is the weakest acid?
A) NH4+
B) C5H5NH+
C) H3NOH+
D) NH3CH3+
E) NH4+ and NH3CH3+
42) Which of the following ions will act as a weak base in water?
A) OH-
B) Cl-
C) NO3-
D) ClO-
E) None of the above will act as a weak base in water.
43) Which of the following ions will act as a weak base in water?
A) HS-
B) F-
C) NO2-
D) ClO-
E) All of the above will act as a weak base in water.
44) Which of the following aqueous solutions has the highest [OH-]?
A) a solution with a pH of 3.0
B) a 1 × 10-4 M solution of HNO3
C) a solution with a pOH of 12.0
D) pure water
E) a 1 × 10-3 M solution of NH4Cl
45) Which of the following aqueous solutions has the lowest [OH-]?
A) a solution with a pH of 3.0
B) a 1 × 10-4 M solution of HNO3
C) a solution with a pOH of 12.0
D) pure water
E) a 1 × 10-3 M solution of NH4Cl
46) A 0.0035 M aqueous solution of a particular compound has pH = 2.46. The compound is __________.
A) a weak base
B) a weak acid
C) a strong acid
D) a strong base
E) a salt
47) Of the following substances, an aqueous solution of __________ will form basic solutions.
NaHS Cu(NO3)2 KHCO3 NaF
A) NaHS, Cu(NO3)2
B) KHCO3, NaHS
C) NaF only
D) NaF, KHCO3
E) NaHS, KHCO3 and NaF
48) Of the following substances, an aqueous solution of __________ will form basic solutions.
NH4Cl Cu(NO3)2 K2CO3 NaF
A) NH4Cl, Cu(NO3)2
B) K2CO3, NH4Cl
C) NaF only
D) NaF, K2CO3
E) NH4Cl only
49) A 0.1 M aqueous solution of __________ will have a pH of 7.0 at 25.0°C.
NaOCl KCl NH4Cl Ca(OAc)2
A) NaOCl
B) KCl
C) NH4Cl
D) Ca(OAc)2
E) KCl and NH4Cl
50) Of the compounds below, a 0.1 M aqueous solution of __________ will have the highest pH.
A) KCN, Ka of HCN = 4.0 × 10-10
B) NH4NO3, Kb of NH3 = 1.8 × 10-5
C) NaOAc, Ka of HOAc = 1.8 × 10-5
D) NaClO, Ka of HClO = 3.2 × 10-8
E) NaHS, Kb of HS- = 1.8 × 10-7
51) A 0.1 M solution of __________ has a pH of 7.0.
A) Na2S
B) KF
C) NaNO3
D) NH4Cl
E) NaF
52) An aqueous solution of __________ will produce a basic solution.
A) NH4ClO4
B) KBr
C) NaCl
D) NaHSO4
E) Na2SO3
53) Of the following, which is the strongest acid?
A) HIO
B) HIO4
C) HIO2
D) HIO3
E) The acid strength of all of the above is the same.
54) Of the following, which is the weakest acid?
A) HIO
B) HIO4
C) HIO2
D) HIO3
E) The acid strength of all of the above is the same.
55) Which of the following acids will be the strongest?
A) H2SO4
B) HSO4-
C) H2SO3
D) H2SeO4
E) HSO3-
56) Of the following, which is the strongest acid?
A) HClO
B) HClO3
C) HClO2
D) HClO4
E) HIO
57) In the gas phase reaction below, NH3 is acting as a(n) __________ base but not as a(n) __________ base.
H+
. . |
N + H+ → N
| |
H H H H H H
A) Arrhenius, BrØnsted-Lowry
B) BrØnsted-Lowry, Lewis
C) Lewis, Arrhenius
D) Lewis, BrØnsted-Lowry
E) Arrhenius, Lewis
16.2 Bimodal Questions
1) What is the conjugate acid of NH3?
A) NH3
B) NH2+
C) NH3+
D) NH4+
E) NH4OH
2) What is the conjugate acid of CO3-2?
A) CO2-2
B) HCO2-2
C) H2CO3
D) HCO3-
E) none of the above
3) The conjugate base of HSO4- is __________.
A) OH-
B) H2SO4
C) SO42-
D) HSO4+
E) H3SO4+
4) The conjugate base of H2PO4- is __________.
A) PO4-3
B) H2PO4
C) H3PO4
D) HPO4-2
E) none of the above
5) The conjugate acid of HSO4- is __________.
A) SO42-
B) H2SO4
C) HSO4+
D) H+
E) HSO3+
6) The conjugate acid of CH3NH2 is __________.
A) CH3NH2
B) CH3NH3+
C) CH3NH3+
D) CH3NH+
E) none of the above
7) What is the conjugate base of OH-?
A) O2
B) O-
C) H2O
D) O2-
E) H3O+
8) What is the pH of an aqueous solution at 25.0 °C that contains 3.98 × 10-9 M hydronium ion?
A) 8.400
B) 5.600
C) 9.000
D) 3.980
E) 7.000
9) What is the pOH of an aqueous solution at 25.0 °C that contains 3.98 × 10-9 M hydronium ion?
A) 8.400
B) 5.600
C) 9.000
D) 3.980
E) 7.000
10) What is the pH of an aqueous solution at 25.0 °C that contains 3.98 × 10-9 M hydroxide ion?
A) 8.40
B) 5.60
C) 9.00
D) 3.98
E) 7.00
11) What is the pOH of an aqueous solution at 25.0 °C that contains 3.98 × 10-9 M hydroxide ion?
A) 8.40
B) 5.60
C) 9.00
D) 3.98
E) 7.00
12) Calculate the pOH of a solution at 25.0 °C that contains 1.94 × 10-10 M hydronium ions.
A) 1.94
B) 4.29
C) 7.00
D) 14.0
E) 9.71
13) Calculate the pH of a solution at 25.0 °C that contains 1.94 × 10-10 M hydronium ions.
A) 1.94
B) 4.29
C) 7.00
D) 14.0
E) 9.71
14) Calculate the concentration (in M) of hydronium ions in a solution at 25.0°C with a pOH of 4.223.
A) 5.98 × 10-5
B) 1.67 × 10-10
C) 1.67 × 104
D) 5.99 × 10-19
E) 1.00 × 10-7
15) Calculate the concentration (in M) of hydroxide ions in a solution at 25.0°C with a pOH of 4.223.
A) 5.98 × 10-5
B) 1.67 × 10-10
C) 1.67 × 104
D) 5.99 × 10-19
E) 1.00 × 10-7
16) An aqueous solution contains 0.100 M NaOH at 25.0°C. The pH of the solution is __________.
A) 0.100
B) 1.00
C) 13.00
D) 7.00
E) -1.00
17) An aqueous solution contains 0.150 M HCl at 25.0°C. The pH of the solution is __________.
A) 0.150
B) 1.00
C) 13.00
D) 7.00
E) 0.82
18) HZ is a weak acid. An aqueous solution of HZ is prepared by dissolving 0.020 mol of HZ in sufficient water to yield 1.0 L of solution. The pH of the solution was 4.93 at 25.0°C. The Ka of HZ is __________.
A) 1.2 × 10-5
B) 6.9 × 10-9
C) 1.4 × 10-10
D) 9.9 × 10-2
E) 2.8 × 10-12
19) The pH of a 0.55 M aqueous solution of hypobromous acid, HBrO, at 25.0°C is 4.48. What is the value of Ka for HBrO?
A) 2.0 × 10-9
B) 1.1 × 10-9
C) 6.0 × 10-5
D) 3.3 × 10-5
E) 3.0 × 104
20) The pH of a 0.25 M aqueous solution of hydrofluoric acid, HF, at 25.0°C is 2.03. What is the value of Ka for HF?
A) 2.0 × 10-9
B) 1.1 × 10-9
C) 6.0 × 10-5
D) 3.5 × 10-4
E) none of the above
21) The pH of a 0.60 M aqueous solution of formic acid, HCHO2, at 25.0°C is 1.98. What is the value of Ka for formic acid?
A) 2.0 × 10-5
B) 1.8 × 10-4
C) 6.0 × 10-5
D) 3.5 × 10-4
E) none of the above
22) A 0.15 M aqueous solution of the weak acid HA at 25.0°C has a pH of 5.35. The value of Ka for HA is __________.
A) 3.0 × 10-5
B) 1.8 × 10-5
C) 7.1 × 10-9
D) 1.3 × 10-10
E) 3.3 × 104
23) The Ka of hypochlorous acid (HClO) is 3.00 × 10-8. What is the pH at 25.0°C of an aqueous solution that is 0.0200 M in HClO?
A) +2.45
B) -2.45
C) -9.22
D) +9.22
E) +4.61
24) The Ka of acetic acid (HC2H3O2) is 1.8 × 10-5. What is the pH at 25.0°C of an aqueous solution that is 0.100 M in acetic acid?
A) +2.87
B) -2.87
C) -11.13
D) +11.13
E) +6.61
25) The acid-dissociation constants of sulfurous acid (H2SO3) are Kal = 1.7 × 10-2 and
Ka2 = 6.4 × 10-8 at 25.0°C. Calculate the pH of a 0.163 M aqueous solution of sulfurous acid.
A) 4.53
B) 1.28
C) 1.86
D) 6.21
E) 1.93
26) The acid-dissociation constants of phosphoric acid (H2PO3) are Kal = 7.5 × 10-3, Ka2 = 6.2 × 10-8, and Ka3 = 4.2 × 10-13 at 25.0°C. What is the pH of a 2.5 M aqueous solution of phosphoric acid?
A) 1.82
B) 0.40
C) 2.51
D) 0.86
E) 0.13
27) The pH of a 0.55 M aqueous solution ammonia, NH3, at 25.0°C is 11.50. What is the value of Kb for NH3?
A) 2.0 × 10-9
B) 1.1 × 10-9
C) 6.0 × 10-5
D) 1.8 × 10-5
E) none of the above
28) A 0.15 M aqueous solution of the weak base B at 25.0°C has a pH of 8.88. The value of Kb for B is __________.
A) 3.0 × 10-5
B) 1.8 × 10-5
C) 3.9 × 10-10
D) 1.3 × 10-10
E) none of the above
29) The pH of a 0.30 M solution of a weak acid is 2.67. What is the Ka for this acid?
A) 2.1 × 10-4
B) 4.4 × 10-4
C) 1.5 × 10-4
D) 6.6 × 10-4
E) none of the above
30) Z- is a weak base. An aqueous solution of NaZ is prepared by dissolving 0.350 mol of NaZ in sufficient water to yield 1.0 L of solution. The pH of the solution was 8.93 at 25.0°C. The Kb of Z- is __________.
A) 1.2 × 10-5
B) 6.9 × 10-9
C) 2.1 × 10-10
D) 9.9 × 10-2
E) 2.8 × 10-12
31) The pH of a 0.10 M solution of a weak base is 9.82. What is the Kb for this base?
A) 2.1 × 10-4
B) 4.4 × 10-8
C) 8.8 × 10-8
D) 6.6 × 10-4
E) 2.0 × 10-5
32) Determine the pH of a 0.35 M aqueous solution of CH3N H2 (methylamine). The Kb of methylamine is 4.4 × 10-4.
A) 10.00
B) 3.86
C) 12.09
D) 1.96
E) 13.24
33) An aqueous solution contains 0.050 M of methylamine. The concentration of hydroxide ion in this solution is __________ M. Kb for methylamine is 4.4 × 10-4.
A) 0.050
B) 2.2 × 10-5
C) 2.9 × 10-3
D) 4.5 × 10-3
E) 4.7 × 10-3
34) An aqueous solution contains 0.050 M of methylamine. The concentration of H+ in this solution is __________ M. Kb for methylamine is 4.4 × 10-4.
A) 0.050
B) 2.2 × 10-13
C) 2.9 × 10-13
D) 4.5 × 10-13
E) none of the above
35) The acid-dissociation constant, Ka, for gallic acid is 4.57 × 10-3. What is the base-dissociation constant, Kb, for the gallate ion?
A) 4.57 × 10-3
B) 2.19 × 10-12
C) 5.43 × 10-5
D) 7.81 × 10-6
E) 2.19 × 102
36) The base-dissociation constant, Kb, for pyridine, C5H5N, is 1.4 × 10-9. The acid-dissociation constant, Ka, for the pyridinium ion, C5H5NH+, is __________.
A) 1.0 × 10-7
B) 1.4 × 10-23
C) 7.1 × 10-4
D) 1.4 × 10-5
E) 7.1 × 10-6
37) The Ka for HCN is 4.9 × 10-10. What is the value of Kb for CN-?
A) 2.0 × 10-5
B) 4.0 × 10-6
C) 4.9 × 104
D) 4.9 × 10-24
E) 2.0 × 109
38) Ka for HF is 7.0 × 10-4. Kb for the fluoride ion is __________.
A) 2.0 × 10-8
B) 1.4 × 10-11
C) 7.0 × 10-18
D) 7.0 × 10-4
E) 1.4 × 103
39) Ka for HCN is 4.9 × 10-10. What is the pH of a 0.068 M aqueous solution of sodium cyanide?
A) 0.74
B) 2.96
C) 11.07
D) 13.24
E) 7.00
40) Ka for HX is 7.5 × 10-12. What is the pH of a 0.15 M aqueous solution of NaX?
A) 7.97
B) 1.96
C) 6.00
D) 8.04
E) 12.10
41) The pH of a 0.15 M aqueous solution of NaZ (the sodium salt of HZ) is 10.7. What is the Ka for HZ?
A) 1.6 × 10-6
B) 6.0 × 10-9
C) 8.9 × 10-4
D) 1.3 × 10-12
E) 3.3 × 10-8
16.3 Algorithmic Questions
1) An aqueous solution at 25.0°C contains [H+] = 0.080 M. What is the pH of the solution?
A) 1.10
B) -1.10
C) 13.0
D) 0.0800
E) 1.30 × 10-13
2) The pH of an aqueous solution at 25.0 °C is 10.30. What is the molarity of H+ in this solution?
A) 5.0 × 10-11
B) 2.0 × 10-4
C) 3.70
D) 1.0 × 10-13
E) 2.0 × 1010
3) Calculate the molarity of hydroxide ion in an aqueous solution that has a pOH of 5.00.
A) 1.0 × 10-5
B) 9.00
C) 1.0 × 10-9
D) 5.0 × 10-14
E) 9.0 × 10-14
4) What is the pH of an aqueous solution at 25.0°C in which [H+] is 0.0025 M?
A) 5.99
B) 2.60
C) -2.60
D) -5.99
E) none of the above
5) What is the pOH of an aqueous solution at 25.0°C in which [H+] is 0.0025 M?
A) 8.01
B) 11.40
C) -11.40
D) -8.01
E) none of the above
6) What is the pH of an aqueous solution at 25.0 °C in which [OH-] is 0.0050 M?
A) 5.30
B) -11.70
C) 2.30
D) -2.30
E) 11.70
7) What is the pOH of an aqueous solution at 25.0 °C in which [OH-] is 0.0040 M?
A) 11.60
B) -2.40
C) 2.40
D) -11.60
E) 5.52
8) What is the concentration (in M) of hydronium ions in a solution at 25.0 °C with pH = 4.153?
A) 4.15
B) 9.85
C) 1.42 × 10-10
D) 7.03 × 10-5
E) none of the above
9) What is the concentration (in M) of hydroxide ions in a solution at 25.0 °C with pH = 4.153?
A) 4.15
B) 9.85
C) 1.42 × 10-10
D) 7.03 × 10-5
E) none of the above
10) A 7.0 × 10-3 M aqueous solution of Ca(OH)2 at 25.0°C has a pH of __________.
A) 12.15
B) 1.85
C) 1.4 × 10-2
D) 7.1 × 10-13
E) 11.85
11) What is the pH of a 0.035 M aqueous solution of barium hydroxide?
A) 12.85
B) 12.54
C) 1.46
D) 10.41
E) 1.15
12) What is the pOH of a 0.035 M solution of barium hydroxide?
A) 12.85
B) 12.54
C) 1.46
D) 1.15
E) 10.41
13) The acid-dissociation constant at 25.0°C for hypochlorous acid (HClO) is 3.0 × 10-8. At equilibrium, the molarity of H3O+ in a 0.010 M solution of HClO is __________.
A) 1.7 × 10-5
B) 0.010
C) 5.8 × 10-10
D) 4.76
E) 2.00
14) The Ka of hypochlorous acid (HClO) is 3.0 × 10-8 at 25.0°C. Calculate the pH of a 0.0335 M hypochlorous acid solution.
A) 3.02
B) 9.50
C) 4.50
D) 6.52
E) -3.02
15) The Ka of hydrofluoric acid (HF) at 25.0 °C is 6.8 × 10-4. What is the pH of a 0.15 M aqueous solution of HF?
A) 4.60
B) 2.00
C) 3.64
D) 0.82
E) 1.17
16) The Ka of hydrazoic acid (HN3) is 1.9 × 10-5 at 25.0°C. What is the pH of a 0.40 M aqueous solution of HN3?
A) 0.40
B) 2.16
C) 5.23
D) 2.56
E) -3.46
17) The base-dissociation constant of ethylamine (C2H5NH2) is 6.4 × 10-4 at 25.0 °C. The [H+] in
a 1.6 × 10-2 M solution of ethylamine is __________ M.
A) 3.5 × 10-12
B) 2.9 × 10-3
C) 3.1 × 10-12
D) 3.2 × 10-3
E) 11.46
18) Calculate the pH of a 0.100 M aqueous solution of NH3. The Kb of NH3 is 1.77 × 10-5.
A) 8.95
B) 11.12
C) 2.88
D) 12.12
E) 1.87
19) The acid-dissociation constant of hydrocyanic acid (HCN) at 25.0°C is 4.9 × 10-10. What is the pH of an aqueous solution of 0.080 M sodium cyanide (NaCN)?
A) 11.11
B) 2.89
C) 1.3 × 10-3
D) 7.8 × 10-12
E) 3.9 × 10-11
20) Calculate the pOH of a 0.0627 M aqueous sodium cyanide solution at 25.0°C. Kb for CN-
is 4.9 × 10-10.
A) 9.33
B) 10.00
C) 5.25
D) 1.20
E) 8.75
21) Calculate the pH of a 0.0787 M aqueous sodium cyanide solution at 25.0 °C. Kb for CN-
is 4.9 × 10-10.
A) 9.33
B) 10.00
C) 5.21
D) 1.10
E) 8.79
22) Determine the pH of a 0.35 M aqueous solution of KF. For hydrofluoric acid, Ka = 7.0 × 10-4.
A) 0.46
B) 5.65
C) 8.35
D) 5.01
E) 1.35
23) Determine the pOH of a 0.35 M aqueous solution of KF. For hydrofluoric acid, Ka = 7.0 × 10-4.
A) 0.46
B) 5.65
C) 8.35
D) 5.01
E) 1.35
24) Calculate the pH of 0.586 M anilinium hydrochloride (C6H5NH3Cl) solution in water, given that Kb for aniline is 3.83 × 10-4.
A) 1.82
B) 12.18
C) 5.41
D) 8.59
E) 12.42
25) Calculate the pOH of 0.716 M anilinium hydrochloride (C6H5NH3Cl) solution in water, given that Kb for aniline is 3.83 × 10-4.
A) 1.78
B) 12.22
C) 5.37
D) 8.63
E) 12.42
26) Kb for NH3 is 1.8 × 10-5. What is the pH of a 0.45 M aqueous solution of NH4Cl at 25.0 °C?
A) 2.55
B) 11.45
C) 9.20
D) 4.80
E) 11.23
27) Kb for NH3 is 1.8 × 10-5. What is the pOH of a 0.15 M aqueous solution of NH4Cl at 25.0 °C?
A) 2.78
B) 11.22
C) 8.96
D) 5.04
E) 11.23
28) The Ka for formic acid (HCO2H) is 1.8 × 10-4. What is the pH of a 0.10 M aqueous solution of sodium formate (NaHCO2)?
A) 11.64
B) 5.63
C) 3.39
D) 8.37
E) 4.26
16.4 Short Answer Questions
1) A solution of acetic acid is 2.0% dissociated at 25.0°C. What was the original concentration (in M) of the acetic acid solution? The Ka at 25.0 °C for acetic acid is 1.8 × 10-5.
2) A solution of formic acid is 3.0% dissociated at 25.0°C. What is the original concentration (in M) of the formic acid solution? The Ka at 25.0 °C for formic acid is 1.8 × 10-4.
3) A solution of ammonia is 2.0% ionized at 25.0°C. What was the original concentration (in M) of the ammonia solution? The Kb at 25.0°C for ammonia is 1.8 × 10-5.
4) What is the pH of a sodium acetate solution prepared by adding 0.820 grams of sodium acetate to 100.0 ml of water at 25.0°C? The Ka at 25.0°C for acetic acid is 1.8 × 10-5.
5) What is the pH of a sodium formate solution prepared by adding 0.680 grams of sodium formate to 100.0 ml of water at 25.0°C? The Ka at 25.0°C for formic acid is 1.8 × 10-4.
16.5 True/False Questions
1) In the reaction
BF3 + F- → BF4-
BF3 acts as a Br∅nsted-Lowry acid.
2) An acid containing the COOH group is called a carbo-oxy acid.
3) A Lewis acid is an electron-pair acceptor, and a Lewis base is an electron-pair donor.
Answer:
View Answer