30
Sample Test 2
CHAPTER 16
1. Acids and bases can be defined in several ways. Which of the following are definitions of bases according to these
definitions?
a. a compound the produces hydronium ions in water
b. a proton acceptor
c.
an electron pair acceptor
d. an electron pair donor
e. both b and d statements.
2. When H2SO4 is dissolved in water, which species would be found in the water at equilibrium in measurable
amounts?
a. H2SO4 b. H3SO4 + c. HSO4 - d. SO4 -2 e. OH3. Which of the following is the net ionic equation for the reaction that occurs during the titration of nitrous acid with
potassium hydroxide?
a) HNO2 + K+ + OH- Æ KNO2 + H2O
b) HNO2 + H2O Æ NO2- + H3O+
c) HNO2 + KOH Æ K+ + NO2- + H2O
d) HNO2 + OH- Æ NO2- + H2O
e) H+ + OH- Æ H2O
4. Calculate the pH of a 0.10 M solution of Ca(OH)2.
a) 13.30 b) 13.00 c) 0.20 d) 0.10 e) none of these
5. Which of the following is the equilibrium constant expression for the dissociation of the weak acid HOCl?
a) K = [H+][OCl-] / [HOCl]
b) K = [H+][OCl-]
c) K = [HOCl] / [H+][OCl-]
d) K = [H+][O2-][Cl-] / [HOCl]
e) none of these answers
6. A substance that can accept an electron pair to form a covalent bond is
a. an Arrhenius acid.
c. a Lewis acid.
b. an Arrhenius base.
d. a Bronsted-Lowry base.
7. Which is the WEAKEST among the following acids?
a. HNO2 ; Ka= 4.0 x 10-4. b. HOCl2 ; Ka= 1.2 x 10-2.
c. HOCl ; Ka= 3.5 x 10-8.
d. HCN
; Ka= 4.9 x 10-10.
8. Which of the following dissociation reaction is NOT associated with the definition of Kb
a.
b.
c.
d.
CH3NH2 + H2O <=== CH3NH3+ + OHCH3CH2NH2 + H2O <=== CH3CH2NH3+ + OHHC2H3O2+ H2O <=== H3O++ C2H3O2d. NH3 + H2O <=== NH4++ OH-
9. If the [H+] in an aqueous solution is 2 x 10-4 M, then the [OH-]is (Kw =1.0 x 10-14)
a. 5 x 10-16
b. 2 x 10-13
c. 5 x 10-12
10. The pOH of an aqueous solution at pH = 8 is
a. 10 b. 1 x 10-6 c. 1 x 1010 d. 6 e. 4
d. 2 x 10-16
11. What is the [H+] of a 0.05 M solution of HNO3(a strong acid)?
a. 0.02
b. 1.7
c. 0.05
d. 12
e. 5 x 10-11
e. 12.6
31
12. What is the pOH of a 0.0049 M NaOH (a strong base) solution?
b. 1.0 x 10-12
c. 2.3
d. 7.0
a. 9.8 x 10-3
13. If you know Ka for acetic acid, HC2H3O2, you can calculate the equilibrium constant, Kb, for the reaction,
C2H3O2-+ H2O <== OH- + HC2H3O2, by the equation:
c. Kb= Kw+ Ka
a. Kb= KwKa b. Kb= Kw/Ka
d. Kb= Ka /Kw e. Kb= Kw- Ka
14. For acetic acid (HC2H3O2) Ka = 1.8 x 10-5. What percent of the acid has dissociated in a 0.02 M solution?
a. 10%
b. 6%
c. 3 %
d. 2%
e. 5%
15. If Ka for HCN is 6.2 x 10-10, what is Kb for CN-?
Note: CN- + H2O <== HCN + OH-, Kb = [HCN][OH-] / [CN-]
b) 6.2 x 10-4
c) 1.6 x 10-5 d) 1.6 x 1023 e) none of these
a) 6.2 x 10-24
16. If 50 ml of a 0.01 M HCl solution is titrated with a 0.01 M NaOH solution, what will be the initial pH and the pH
at the endpoint.
a. 2 and 3.5
b. 2 and 7 c. 3.30 and 7 d. 12 and 7 e. None of these
17. What is the pH of a 1.0 M aqueous solution of NaCl?
a) 7.0 b) greater than 7.0
c) less than 7.0
d) there is not enough information given
18. A 50.00-mL sample of 0.100 M KOH is being titrated with 0.100 M HNO3. Calculate the pH of the solution after
52.00 mL of HNO3 is added.
a) 6.50 b) 3.01 c) 2.71 d) 2.41 e) none of these
19. If the following substance is dissolved in pure water, will the solution be acidic, neutral, or basic?
solid sodium carbonate: (Na2CO3).
a) acidic
b) neutral
c) basic
20. A solution prepared by dissolving SO2 in water would be:
a. acidic b. basic c. neutral d. none of the above
21. If a 0.150 M solution of an acid, HCN, has a Ka = 6.2 x 10-10, the pH of the solution is:
a. 4.0
b. 3.0
c. 12.0
d. 5.0
e. 6.0
22. The salt that forms an alkaline (basic) aqueous solution is
a. KNO3.
b. NH4Cl.
d. NaCl.
c. NaC2H3O2.
23. A weak monoprotic acid (HA) is 1.41% dissociated in a 1.0 M solution. The Ka for this acid is
a. 4.0 x 10-6. b. 5.6 x 10-5. c. 2.0 x 10-4. d. 9.9 x 10-3.
24. Milk of magnesia has a pH of 10.40. What is its [OH-]?
a. 1.0 x 10-7 M
b. 2.5 x 10-4 M
c. 4.0 x 10-11 M
25. In an aqueous solution with [H+]= 4.1 x 10-9 M,
a. [OH-]=2.4 x 10-6 M. b. the solution is basic. c. pH=8.39.
d. Each statement is true.
26. A solution which is formed by combining 700. mL of 0.20 M HCl with 300. mL of 0.50 M
NaOH has a [H+] concentration of
32
a. 0.20.
b. 0.020.
c. 0.010.
d. 0.14. e. 1.0 x 10-12.
27. What is the percent dissociation of a 0.145 M propionic acid (CH3CH2COOH) solution? (Ka = 1.3 x 10-5)
a. 0.95
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
b. 1.3
c. 1.8
d. 4.5
e. 5.6
According to the Arrhenius acid-base theory, _____ are responsible for the properties of acidic aqueous
solutions and _____ are responsible for the properties of basic aqueous solutions.
a. hydrogen atoms; oxygen atoms
b. oxygen atoms; hydrogen atoms
c. hydronium ions; hydroxide ions
d. hydronium ions; water molecules
e. hydrogen ions; nitrogen atoms
A Bronsted-Lowry acid is a(an) _____ in aqueous solution and a Bronsted-Lowry base is a(an) _____ in aqueous
solution.
a. hydrogen atom acceptor; hydrogen atom donor
b. electron acceptor; electron pair donor
c. nitrogen atom donor; nitrogen atom acceptor
d. hydrogen ion acceptor; nitrogen atom donor
e. hydrogen ion donor; hydrogen ion acceptor
A Bronsted-Lowry base must have a(an) ___________.
a. atom that does not obey the octet rule
b. nitrogen atom
c. hydroxide ion
d. atom with an unshared pair of electrons
e. amphiprotic atom
All of the following can act as Bronsted-Lowry bases except
b. H2O c. NH3 d. PO43- e. HSO4a. Al3+
Because water can act as a Bronsted-Lowry acid or base, it is said to be __________.
a. acidic b. amphiprotic c. basic d. strong e. weak
Which reaction illustrates water acting as a base?
a. HSO4- + H2O -> H3O+ + SO42b. HPO42- + H2O -> OH- + H3PO4
c. NH3 + H2O -> NH4+ + OHd. Cu(H2O)42+ + 4NH3 -> Cu(NH3)42+ + 4H2O
e. H2CO3 -> H2O + CO2
When the weak base pyridine reacts with water, the products are _____ and _____. The formula for pyridine is C5H5N.
a. H+ and OH- b. H3O+ and OH- c. H3O+ and C5H6N+ d. OH- and C5H6N+
e. OH- and C5H4NWhich of the following is a conjugate acid-base pair?
CH3COOH and OHa. H+ and OH- b. CH3COOH and CH3COO- c.
+
+
d. CH3COOH and H e. CH3COOH and H3O
The conjugate acid of NH3 is __________.
a. NH2- b. NH4+ c. H+ d.H3O+ e. NH4OH
Organic compounds classified as acids generally have the formula _____.
a. R-NH2 b. R-COOH c. R-OH d. R-CHO e.
CH3 -(CH2)n-CH3
Organic compounds classified as bases often have the formula _____.
a. R-NH2 b. R-COOH c. R-OH d. R-CHO e. CH3 –(CH2)n-CHWhich of the following contributes to the acidity of the hydrogen atom in the carboxylic acid functional group?
33
a.
b.
c.
d.
e.
the electronegativity of the O that is bonded to the H
the attraction of the other atom of O for the electrons in the O-H bond
resonance stabilization of the resulting anion
the lack of polarity in the C-H bonds in the rest of the molecule
all of these
40. The reaction between butanoic acid and water is written as _____. The formula for butanoic acid is CH3CH2CH2COOH.
a. CH3CH2CH2COOH + H2O <===> CH2CH2CH2COOH + H3O+
b. CH3CH2CH2COOH + H2O <===> CH3CH2CH2COO- + OHc. CH3CH2CH2COOH + H2O <===> CH3CH2CH2COO- + H3O+
d. CH3CH2CH2COOH + H2O <===> CH3CH2CH2COOH2 + OHe. CH3CH2CH2COOH + H2O <===> CH3CH2CHCOOH- + H3O+
41. The reaction between ethylamine, an organic base, and hydrochloric acid is written as _____. The formula for ethylamine is
CH3CH2NH2.
a. CH3CH2NH2 + HCl <===> CH4CH2NH2+Clb. CH3CH2NH2 + HCl <===> CH3CH3NH2+Clc. CH3CH2NH2 + 2HCl <===> CH3CH2NH42+Cl2d. CH3CH2NH2 + HCl <===> CH3CH2NH3+Cle. CH3CH2NH2 + HCl <===> CH3CH2NH-H2Cl+
42. Classify each compound as a carboxylic acid or an amine.
(CH3)2NH
CH3COOH
C6H5COOH
a. acid, acid, amine
b. amine, acid, amine
c. amine, amine, acid
d. acid, amine, acid
e. acid, acid, acid
43. The reaction between water molecules is called _____, and the value of the equilibrium constant for the reaction at 25ºC is
_____.
a. neutralization; 1.0 x 106
b. autoionization; 1.0 x 10-14
c. protonation; 5.5 x 10-14
d. hydrolysis; 1.0 x 10-14
e. autoionization; 1.0 x 1014
44. A neutral solution is one in which
a. [H+] > [OH-] and [H+] > 1.0 x 10-7 M
b. [H+] < [OH-] and [H+] < 1.0 x 10-7 M
c. [H+] = [OH-] = 1.0 x 10-7 M
d. [H+] = [OH-] = 1.0 x 10-14 M
e. [H+] = [OH-] = 1.0 x 10+7 M
45. An acidic solution is one in which
a. [H+] > [OH-] and [H+] > 1.0 x 10-7 M
b. [H+] < [OH-] and [H+] < 1.0 x 10-7 M
c. [H+] = [OH-] = 1.0 x 10-7 M
d. [H+] = [OH-] = 1.0 x 10-14 M
e. [H+] = [OH-] = 1.0 x 10+7 M
46. A basic solution is one in which
a. [H+] > [OH-] and [H+] > 1.0 x 10-7 M
b. [H+] < [OH-] and [H+] < 1.0 x 10-7 M
c. [H+] = [OH-] = 1.0 x 10-7 M
d. [H+] = [OH-] = 1.0 x 10-14 M
e. [H+] = [OH-] = 1.0 x 10+7 M
47. Calculate the pH and pOH in a 1.2 M KOH solution, a strong base. pH = _____, and pOH = _____.
34
48.
49.
50.
51.
52.
a. 1.2 M; 1.2 M b. 1.2 M; 8.3 x 10-15 M c. 8.3 x 10-15 M; 1.2 M d. 8.3 x 10-15 M; 1.0 x 10-14 M
e. 1.0 x 10-7 M; 1.0 x 10-7 M
Calculate the [H+] and [OH-] in a 1.2 M HClO4 solution, a strong acid. [H+] = _____, and [OH-] = _____.
a. 1.2 M; 1.2 M b. 1.2 M; 8.3 x 10-15 M c. 8.3 x 10-15 M; 1.2 M d. 8.3 x 10-15 M; 1.0 x 10-14 M
e. 1.0 x 10-7 M; 1.0 x 10-7 M
Calculate the pH of a solution where [H+] = 4.6 x 10-4. Is this solution acidic or basic?
a. 4.60; acidic b. 4.60: basic c. 3.34; acidic
d. 3.34; basic e. 10.66; acidic
Calculate the pH of a solution where [OH-] = 4.6 x 10-4. Is this solution acidic or basic?
a. 4.60; basic b. 10.66; basic c. 10.66; acidic
d. 3.34; basic e. 3.34; acidic
The pH of an egg mixture used in pet food is 6.24. Calculate the value of [H+]. Is the solution acidic or basic?
a. 0.80 M; acidic b.
5.75 x 10-7 M; basic c.
5.75 x 10-7 M; acidic d. 1.74 x 10-8 M; acidic
-8
e. 1.74 x 10 M; basic
Arrange the solutions in order of increasing acidity:
I.
indicator with [H+] = 4.2 x 10-6 M
II.
lemonade, pH = 2.65
III.
0.25 M nitric acid
IV.
pickle juice, pH = 3.10
a. III-II-I-IV
b. III-II-IV-I
c. II-IV-III-I
d. I-IV-II-III
e. IV-I-II-III
53. Phenolphthalein is an acid-base indicator that is colorless in its acid form and pink in its basic form, changing at pH = 8.5.
Bromcresol green is yellow in its acidic form and blue in its basic form, changing at pH = 4.8. A solution is colorless in
phenolphthalein and blue in bromcresol green. Therefore we can conclude that the pH of the solution is __________.
a. less than 4.8 b. exactly 7.0 c. between 4.8 and 8.5 d. between 7.0 and 8.5
e. greater than 8.5
54. Write the acid ionization constant expression for the ionization of acetic acid, CH3COOH, in aqueous solution.
a.
[CH COOH]
Ka =
b.
Ka
c.
d.
e.
Ka
Ka
Ka
3
[CH 3 COO- ][H 3 O + ]
[CH 3 COO - ][H 3 O + ]
=
[CH 3 COOH]
[CH 3 COOH][OH - ]
=
[CH 3 COO- ][H 2 O]
[CH 3 COOH][H 3 O + ]
=
[CH 3 COO - ][H 2 O]
[CH 3 COO - ][H 2 O]
=
[CH 3 COOH][H 3 O + ]
55. Write the acid ionization constant expression for the ionization of the hydrogen sulfate ion, HSO 4− , in aqueous solution.
a.
[HSO ][H O]
Ka =
4−
2−
2
[SO 4 ][H 3 O + ]
35
b.
c.
d.
e.
Ka =
[HSO 4− ][H 2 O]
[H 2 SO 4 ][H 3 O + ]
[H 2 SO 4 ][H 3 O + ]
Ka =
[HSO 4− ]
[SO 24- ][H 3 O + ]
Ka =
[HSO 4− ]
[H 2 SO 4− ][OH - ]
Ka =
[HSO 4− ]
56. Which statement about a 0.50 M sample of the weak acid, HNO2, Ka = 4.5 x 10-4, is not correct?
a. [H+] = 0.50 M.
b. The acid is only slightly ionized.
c. The sample contains mostly un-ionized HNO2 molecules.
d. The pH is slightly less than 2.0.
e. [H+] > [OH-].
57. Which acid is polyprotic?
a. acetic acid b. nitric acid c. nitrous acid d. phosphoric acid
e. perchloric acid
58. In a polyprotic acid, the value of Ka1 will be _____ the value of Ka2 because _____.
a. the same as; both hydrogen ions are bonded to the same anion
b. larger than; it is easier to remove a hydrogen ion from a neutral molecule than from an anion
c. larger than; it is easier to remove a hydrogen ion from a neutral molecule than from a cation
d. smaller than; it is easier to remove a hydrogen ion from a neutral molecule than from an anion
e. smaller than; it is easier to remove a hydrogen ion from a neutral molecule than from a cation
59. The pH of a solution of a 0.15 M solution of HOCl is 4.14. What is the Ka for HOCl?
8.8 x 10-3
a. 3.5 x 10-8 b. 4.8 x 10-4 c. 5.7 x 10-2 d. 7.2 x 10-5 e.
-7
60. The value of the ionization constant for HA is 4.2 x 10 . What is the pH of a 0.35 M solution of this acid?
a. 3.8 x 10-4 b. 1.5 x 10-7 c. 3.19 d. 3.42 e. 6.83
61. Calculate the pH of a 0.14 M solution of an acid with Ka = 6.2 x 10-8.
a. 0.85 b.
4.03 c. 6.35 d. 7.21 e. 8.06
62. For the basic compound strychnine, the value of Kb is 1.8 x 10-6. What is the pH of a 0.085 M solution of this poison?
a. 3.41 b. 6.81 c. 7.18 d. 10.59 e. 11.66
63. Which is the weakest acid?
a. HBr b. HCl c. HF d. HI
e. More information is needed to answer this question.
64. Which compound is the most acidic?
a. AsH3 b. HBr c. GeH4 d. H2Se
e. More information is needed to answer this question.
65. At pH = 4.5, the amino acid aspartic acid will exist in its _____ form.
a. acidic b. basic c. resonance d. un-ionized e. zwitterion
66. An aqueous solution of potassium perchlorate in pure water is predicted to be ___________.
a. strongly acidic
b. weakly acidic c. neutral d. weakly basic
e. strongly basic
67. An aqueous solution of potassium benzoate is predicted to be ___________.
a. strongly acidic b. weakly acidic c. neutral d. weakly basic
e. strongly basic
68. A solution of pyridinium hydrochloride is predicted to be ___________.
a. strongly acidic b. weakly acidic c. neutral
d. weakly basic e. strongly basic
36
69. The reaction between the ion of a weak acid or a weak base and water is called a(an) _____ reaction.
a. neutralization b. autoionization c. protonation d.hydrolysis e. decomposition
70. Which compound would not be used as an antacid for the treatment of heartburn?
a. Al(OH)3 b. CaCO3 c. KOH d. Mg(OH)2 e. NaHCO3
71. Acid-base chemistry causes some baked goods to "rise" by producing
a. carbon dioxide when an acid reacts with sodium bicarbonate in baking soda.
b. hydrogen gas from trace metals that react with acids in the batter.
c. steam from the water formed in neutralization.
d. carbon dioxide and ethanol as fermentation products.
e. sulfur dioxide from sulfite-containing foods.
72. Drain cleaners cause grease to dissolve by a(an) _____ reaction.
a.
combustion b. esterification c. hydrogenation d. neutralization e. saponification
73. The association between a Lewis acid and a Lewis base is called a(an) _____ bond.
a. acidic b. coordinate covalent c. hydrogen d. ionic e.
metallic
74. Metal hydroxides that can act either as Lewis acids or Lewis bases are described as _____.
a. acidic
b. amphoteric c. basic d. hydrated
e. neutral
Answers to Questions
1. e. both b and d statements.
2. c. HSO43. d) HNO2 + OH- ---- NO2- + H2O
4. a) 13.30
5. a) K = [H+][OCl-] / [HOCl]
6. c. a Lewis acid.
7. d. HCN
; Ka= 4.9 x 10-10.
8. c. HC2H3O2+ H2O <=== H3O++ C2H3O29. e. 5 x 10-11
10. d. 6
11. c. 0.05
12. c. 2.3
13. b. Kb= Kw/Ka
14. c. 3 %
15. c) 1.6 x 10-5
16. b) 2 and 7
17. a. 7.0
18. c. 2.71
19. c. basic
20. a. acidic
21. d. 5.0
22. c. NaC2H3O2.
23 c. 2.0 x 10-4.
24. d. 5 x 10-4 M
25. e. Each statement is true.
26.1.0 x 10-12.
27. a. 0.95
28. c. hydronium ions; hydroxide ions
29. e. hydrogen ion donor; hydrogen ion acceptor
30. d. atom with an unshared pair of electrons
31. a. Al3+
32. b. amphiprotic
33. a. HSO4- + H2O -> 3O+ + SO4234. d. OH- and C5H6N+
37
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
b. CH3COOH and CH3COOb. NH4+
b. R-COOH
a. R-NH2
e. all of these
c. CH3CH2CH2COOH + H2O <===> CH3CH2CH2COO- + H3O+
d. CH3CH2NH2 + HCl <===> CH3CH2NH3+Cld. acid, amine, acid
b. autoionization; 1.0 x 10-14
c. [H+] = [OH-] = 1.0 x 10-7 M
a. [H+] > [OH-] and [H+] > 1.0 x 10-7 M
b. [H+] < [OH-] and [H+] < 1.0 x 10-7 M
c. 8.3 x 10-15 M; 1.2 M
b. 1.2 M; 8.3 x 10-15 M
c. 3.34; acidic
b. 10.66; basic
c. 5.75 x 10-7 M; acidic
d. I-IV-II-III
c. between 4.8 and 8.5
54. . b.
55. d.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
[CH 3 COO - ][H 3 O + ]
[CH 3 COOH]
2[SO ][H O + ]
Ka =
Ka =
+
4
3
[HSO 4− ]
a. [H ] = 0.50 M.
d. phosphoric acid
b. larger than; it is easier to remove a hydrogen ion from a neutral molecule than from an anion
a. 3.5 x 10-8
d. 3.42
b. 4.03
d. 10.59
c. HF
b. HBr
a. acidic
c. neutral
d. weakly basic
b. weakly acidic
d.hydrolysis
c. KOH
a. carbon dioxide when an acid reacts with sodium bicarbonate in baking soda.
e. saponification
b. coordinate covalent
b. amphoteric