IB Topics 8 & 18 Multiple Choice Practice
1. What will happen if the pressure is increased in the following reaction mixture at equilibrium?
CO2 (g) + H2O (l)
H+ (aq) + HCO3− (aq)
A. The equilibrium will shift to the right and pH will decrease.
B. The equilibrium will shift to the right and pH will increase.
C. The equilibrium will shift to the left and pH will increase.
D. The equilibrium will shift to the left and pH will decrease.
2. 10.0 cm3 of an aqueous solution of sodium hydroxide of pH = 10 is mixed with 990.0 cm3 of distilled
water. What is the pH of the resulting solution?
A. 8
B. 9
C. 11
D. 12
3. Which statement is incorrect for a 0.10 mol dm–3 HCOOH solution?
A. pH = 1
B. [H+] << 0.10 mol dm–3
C. [HCOO–] is approximately equal to [H+]
D. HCOOH is partially ionized
4. Which is an acid-base conjugate pair?
A. H3O+ / OH–
B. H2SO4 / SO42–
C. CH3COOH / H3O+
D. CH3NH3+ / CH3NH2
5. Which 1.0 mol dm–3 solution has the highest pH?
A. Ammonium chloride
B. Sulfuric acid
C. Sodium chloride
D. Ammonia
6. Which of the following is correct?
A. A weak acid is a proton donor and its aqueous solution shows good conductivity.
B. A weak acid is a proton donor and its aqueous solution shows poor conductivity.
C. A weak acid is a proton acceptor and its aqueous solution shows good conductivity.
D. A weak acid is a proton acceptor and its aqueous solution shows poor conductivity.
7. Which of the following will form a buffer solution if combined in appropriate molar ratios?
A. HCl and NaCl
B. NaOH and HCOONa
C. NH4Cl and HCl
D. HCl and NH3
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8. Which indicator is appropriate for the acid-base titration shown below?
A. Thymol blue (pKa = 1.5)
B. Methyl orange (pKa = 3.7)
C. Bromophenol blue (pKa = 4.2)
D. Phenolphthalein (pKa = 9.6)
9. Which species produced by the successive dissociations of phosphoric acid, H3PO4, are amphiprotic?
A. HPO42− and PO43−
B. H2PO4− and HPO42−
C. H2PO4− and PO43−
D. HPO42− only
10. What is the pH of 1.0 × 10−3 mol dm−3 sodium hydroxide, NaOH(aq)?
A. 3
B. 4
C. 10
D. 11
Kw = 1.0 × 10−14
11. Which species acts as a Lewis and Brønsted–Lowry base?
A. [Al(H2O)6]3+
B. BF3
C. NH4+
D. OH−
12. A buffer is produced by mixing 20.0 cm3 of 0.10 mol dm−3 ethanoic acid, CH3COOH(aq), with 0.10 mol
dm−3 sodium hydroxide, NaOH(aq). What is the volume of NaOH required and the pH of the buffer?
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13. Which type of bond is formed when a Lewis acid reacts with a Lewis base?
A. Covalent
B. Dipole-dipole
C. Double
D. Hydrogen
14. What is the order of increasing acidity of the following acids?
A. chloroethanoic < ethanoic < hydrogen fluoride < hydrogen cyanide
B. ethanoic < chloroethanoic < hydrogen fluoride < hydrogen cyanide
C. chloroethanoic < ethanoic < hydrogen cyanide < hydrogen fluoride
D. hydrogen cyanide < ethanoic < hydrogen fluoride < chloroethanoic
15. Which species behave as Brønsted–Lowry bases in the following reaction?
H2SO4 + HNO3
H2NO3+ + HSO4A. HNO3 and HSO4
B. HNO3 and H2NO3+
C. H2SO4 and HSO4D. H2NO3+ and HSO416. Which is a conjugate Brønsted–Lowry acid-base pair?
A. CH3COO− / H3O+
B. H2O / CH3COO−
C. H2O / H3O+
D. CH3COOH / H2O
17. Which of the following gases does not result in acid deposition?
A. CO2
B. NO2
C. NO
D. SO2
18. What occurs when solid sodium hydrogen carbonate reacts with aqueous sulfuric acid?
A. Bubbles of sulfur dioxide form.
B. Bubbles of both hydrogen and carbon dioxide form.
C. Bubbles of hydrogen form.
D. Bubbles of carbon dioxide form.
19. A student carried out a titration to determine the concentration of an acid and found that his value had
good precision but poor accuracy. Which process explains this outcome?
A. Consistently overshooting the volume of solution from the burette into the flask.
B. Collection of insufficient titration data.
C. Reading the meniscus in the burette at a different angle each time.
D. Forgetting to rinse the flask after one of the titrations.
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20. Aqueous solutions of a weak acid and a strong acid of equal concentration are compared. Which
statements are correct?
I. The weak acid is less dissociated than the strong acid.
II. The strong acid reacts with a metal oxide but the weak acid does not.
III. The strong acid has greater conductivity than the weak acid.
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
21. Which mixture is a buffer solution?
A. 25 cm3 of 0.10 mol dm-3 NH3 (aq) and 50 cm3 of 0.10 mol dm-3 HCl (aq)
B. 50 cm3of 0.10 mol dm-3 NH3 (aq) and 25 cm3 of 0.10 mol dm-3 HCl (aq)
C. 25 cm3 of 0.10 mol dm-3 NaOH (aq) and 25 cm3 of 0.10 mol dm-3 HCl (aq)
D. 50 cm3 of 0.10 mol dm-3 NaOH (aq) and 25 cm3 of 0.10 mol dm-3 HCl (aq)
22. The diagram represents the bonding in aluminium chloride.
Which statement is correct?
A. The aluminium atoms behave as Lewis acids.
B. The aluminium atoms behave as Lewis bases.
C. One aluminium atom is a Lewis base and the other a Lewis acid.
D. One chlorine atom is a Lewis base and the other a Lewis acid.
23. Which titration curve would occur when a weak acid is added to a strong base?
24. Which salt solution has the highest pH?
A. NH4Cl
B. Ca(NO3)2
C. Na2CO3
D. K2SO4
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25. Which gas in the atmosphere causes the pH of unpolluted rain to be approximately 6?
A. Carbon dioxide
B. Sulfur dioxide
C. Oxygen
D. Nitrogen
26. Which compound is a strong acid?
A.
B.
C.
D.
27. Which species cannot function as a Lewis acid?
A.
B.
C.
D.
28.
of a solution of a strong acid with a pH of 3 is added to a volumetric flask and the total
volume is made up to
by adding distilled water. The resulting solution is then thoroughly mixed.
What is the pH of the diluted solution?
A. 1
B. 2
C. 4
D. 5
29. The forward reaction of this equilibrium is endothermic.
What is correct about water at 50 °C?
A.
B.
C.
D.
30. Which equation represents a reaction for which a base dissociation constant expression,
written?
, can be
A.
B.
C.
D.
31. An equal amount of each of the following salts is added separately to the same volume of water.
Which salt will have the greatest effect on the pH of water?
A.
C. RbCl
B.
D. KBr
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32. Which mixture will form a buffer in aqueous solution?
A.
B.
C.
D.
33. Which statements are correct about the complex
I. Oxidation state of copper is +2.
II. Ammonia is a ligand.
III. Chloride ions act as Lewis acids.
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
?
34. The strengths of four acids are:
glycine
chloroethanoic acid
phenol
butanoic acid
What is the order of increasing acid strength?
A.
B.
C.
D.
35. Which compound forms an acidic solution when dissolved in water?
A.
B.
C.
D.
36. For which titration can the end point not be determined accurately by using an acid-base indicator?
A.
B.
C.
D.
37. Which definition of a base is correct?
A. A Lewis base accepts a proton.
B. A Brønsted-Lowry base accepts an electron pair.
C. A Brønsted-Lowry base donates an electron pair.
D. A Lewis base donates an electron pair.
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38. A student adds 0.3 g of magnesium metal to equal volumes of hydrochloric acid and ethanoic acid of the
same concentrations in separate flasks. Which statement is correct?
A. Hydrochloric acid reacts more rapidly as it has a higher pH than ethanoic acid.
B. A greater total volume of
gas is produced with hydrochloric acid than with ethanoic acid.
C. The same total volume of
gas is produced with both hydrochloric acid and ethanoic acid.
D. Ethanoic acid reacts more slowly because it has a lower pH than hydrochloric acid.
39. Which are acid-base pairs according to the Brønsted‒Lowry theory?
I.
II.
III.
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
40. A solution of
A. 3
B. 4
C. 5
D. 6
hydrochloric acid has a pH of 4. What is the final pH if
41. Which compound reacts with calcium oxide, CaO?
A.
B.
C.
D. MgO
42. Which statement explains why ammonia,
A. It can accept a proton.
B. It can accept a lone pair of electrons.
C. It can donate a lone pair of electrons.
D. It can donate a proton.
, is classified as a Lewis base?
43. Which definition of a base is correct?
A. A Lewis base accepts a proton.
B. A Brønsted-Lowry base accepts an electron pair.
C. A Brønsted-Lowry base donates an electron pair.
D. A Lewis base donates an electron pair.
44. Which compound will produce an aqueous solution which has a pH greater than 7?
A.
B.
C.
D.
7
of water is added?
45. Methylamine acts as a weak base when it reacts with water. For a diluted aqueous solution, what is the
expression for this reaction?
A.
B.
C.
D.
46. The acid–base indicator phenol red, HIn, changes colour from yellow to red over a pH range of 6.6–8.2.
Which statement is correct?
A. In a strongly acidic solution
.
B. The
of phenol red is between 6.6 and 8.2.
C. The
ions are yellow.
D. Phenol red would be a suitable indicator for the titration of a strong acid and a weak base.
47. Cobalt forms the complex
. Which statements are correct for this complex?
I. The cobalt ion acts as a Lewis acid.
II. The cobalt ion has an oxidation number of +II.
III. There are 90° bond angles between the cobalt ion and the ligands.
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
48. In which reaction does
act as a Lewis base but not as a Brønsted–Lowry base.
A.
B.
C.
D.
49. The
of
is 7.08. What is its conjugate acid and what is the
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value of the acid?
50. Which mixture of solutions can be used to prepare a buffer solution?
A.
and
B.
and
C.
and
D.
and
51. A weak acid is titrated with a strong base. Which statement is true for the titration curve?
A. A is the equivalence point.
B. The pH at A equals the
of the acid.
C. The pH at B equals 7.
D. C is in the buffer region.
52. Methyl orange is an indicator which changes its
colour from red to yellow in a pH range of 3.2 – 4.4.
For which titration would methyl orange be a
suitable indicator?
A. Iodine and sodium thiosulfate solution
B. Hydrochloric acid and ammonia solution
C. Ethanoic acid and sodium hydroxide solution
D. Ethanoic acid and ammonia solution
53. What is the conjugate base of phenol,
A.
C.
–OH
?
B.
D.
–
–OH
54. Which compounds can be mixed together as aqueous solutions of equal volume and concentration to
form an acidic buffer solution?
A. Sodium hydrogensulfate and sulfuric acid
B. Sodium propanoate and propanoic acid
C. Ammonium chloride and ammonia solution
D. Sodium chloride and hydrochloric acid
55. Which statements about an acid–base indicator are correct?
I. It can be a weak acid.
II. It is a substance in which the conjugate acid/base pair are different colours.
III. It can be a weak base.
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
56. What is the expression for the ionic product constant of water,
A.
B.
C.
D.
9
?
57. Which graph would be obtained by adding
to
of
?
58. What are the conjugate acid–base pairs in the following reaction?
59. Which group of three compounds contains only weak acids and bases?
60. A solution of acid HX has a pH = 1 and a solution of acid HY has a pH = 3. Which statement must be
correct?
A. HX is a stronger acid than HY.
B. HY is a stronger acid than HX.
C. The
in the solution of HX is 100 times greater than the
in the solution of HY.
D. The
in the solution of HY is 100 times greater than the
in the solution of HX.
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61. Which list contains only strong bases?
A. ammonia, sodium hydroxide, ethylamine
B. potassium hydroxide, ammonia, sodium hydroxide
C. lithium hydroxide, potassium hydroxide, barium hydroxide
D. ammonia, ethylamine, barium hydroxide
62. Which products would be formed when hydrochloric acid reacts with magnesium oxide?
A. magnesium chloride and carbon dioxide
B. magnesium chloride, hydrogen gas and water
C. magnesium, hydrogen gas and water
D. magnesium chloride and water
63. Equal volumes and concentrations of hydrochloric acid and ethanoic acid are titrated with sodium
hydroxide solutions of the same concentration. Which statement is correct?
A. The initial pH values of both acids are equal.
B. At the equivalence points, the solutions of both titrations have pH values of 7.
C. The same volume of sodium hydroxide is needed to reach the equivalence point.
D. The pH values of both acids increase equally until the equivalence points are reached.
64. Which mixtures could act as buffers?
I. NaOH(aq) and HCl(aq)
II. NaOH(aq) and CH3COOH
III. HCl(aq) and CH3COONa(aq)
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
65. The table below shows data for the
and
values for some acids and bases at 298 K.
Which two formulas represent the weakest acid and the weakest base in the table?
A. HClO and
B.
and
C.
and
D. HClO and
66. Which pair of compounds could be used to make a buffer solution (assuming appropriate molar ratios)?
A. KCl and HCl
B. NaCl and HCl
C.
and
D.
and
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67. The values of
, the ionic product constant of water, are:
Which statements are correct?
I. The
in water is less than the
at 18 °C.
II. The ionization of water is an endothermic process.
III. The pH of water is lower at 25 °C than at 18 °C.
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
68. For which equilibrium can an expression for a base dissociation constant,
be written?
, for the forward reaction
A.
B.
C.
D.
69. The colours of three indicators are shown in the table below.
Equal volumes of these three indicators were mixed and the mixture was added to a solution of
. What colour would be seen?
A. Yellow
B. Orange
C. Green
D. Blue
70. Which of the following is an example of a Lewis acid–base reaction, but not a Brønsted–Lowry acid–
base reaction?
A.
B.
C.
D.
71. The
value of ammonia is 4.75 at 298 K. What is the
A.
B.
C.
D.
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value of the ammonium ion?
72. Which indicator would be the most appropriate for titrating aqueous ethylamine, CH3CH2NH2, with
nitric acid, HNO3?
A. Bromophenol blue (pKa= 4.1)
B. Bromothymol blue (pKa= 7.3)
C. Phenol red (pKa= 8.0)
D. Thymolphthalein (pKa= 10.0)
73. Which substance can act as a Lewis acid but not as a Brønsted–Lowry acid?
A. HCl
B. CH3COOH
C. BF3
D. CF3COOH
74. Which row correctly describes
75. What is the Brønsted–Lowry conjugate base of
A.
?
?
B.
C.
D.
76. Three aqueous solutions of nitric acid are listed below.
W.
X.
Y.
What is the correct order of increasing pH of these solutions?
A.
B.
C.
D.
77. Which salts will dissolve in water to give solutions with a pH above 7?
I.
II.
III.
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
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78. During a titration,
sodium hydroxide is added to
indicator would be the best to use as an end point indicator in this titration?
ethanoic acid. Which
79. Which reaction represents an acid–base reaction according to the Lewis theory but not according to the
Brønsted–Lowry theory?
A.
B.
C.
D.
80. Four aqueous solutions are listed below.
W.
X.
Y.
Z.
What is the correct order of increasing pH of these solutions?
A.
B.
C.
D.
81. Which mixtures are buffer solutions?
I.
and
II.
III.
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
and
and
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82. Which titration curve is produced by the titration of
of
NaOH with
?
83. Which descriptions are correct for both a Brønsted–Lowry acid and a Lewis acid?
84. What is the pH of the solution formed when
water?
A. 1.5
B. 2.0
C. 2.5
D. 3.0
of HCl(aq) with pH 1.0 is added to
85. Consider the equilibrium below.
Which species represent a conjugate acid-base pair?
A.
and
B.
C.
D.
and
and
and
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of
86. Which is not a conjugate acid-base pair?
A.
and
B.
and
C.
and
D.
and
87. Which
A. HCl
B.
C.
D.
solution would have the highest conductivity?
88. The pH of a solution changes from
hydrogen ions during this pH change?
A. It decreases by a factor of 1000
B. It increases by a factor of 1000
C. It decreases by a factor of 100
D. It increases by a factor of 100
to
. What happens to the concentration of the
89. Consider the equation for the dissociation of water:
Which statement is correct?
A. The pH of pure water is always 7.
B. At temperatures above 298 K the pH of pure water is below 7.
C. At temperatures above 298 K the pH of pure water is above 7.
D.
decreases with increasing temperature.
90. The
value for a base is
at this temperature?
A.
B.
C.
D.
at 298 K. What is the
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value for its conjugate acid
1. A
2. A
3. A
4. D
5. D
6. B
7. D
8. D
9. B
10. D
11. D
12. D
13. A
14. D
15. A
16. C
17. A
18. D
19. A
20. B
21. B
22. A
23. B
24. C
25. A
26. B
27. C
28. D
29. C
30. D
31. A
32. D
33. A
34. D
35. A
36. A
37. D
38. C
39. B
40. C
41. C
42. C
43. D
44. C
45. A
46. B
47. B
48. D
49. A
50. A
51. B
52. B
53. C
54. B
55. D
56. A
57. B
58. C
59. B
60. C
61. C
62. D
63. C
64. C
65. A
66. D
67. C
68. B
69. A
70. B
71. C
72. A
73. C
74. A
75. B
76. B
77. A
78. D
79. D
80. B
81. C
82. C
83. B
84. D
85. C
86. C
87. A
88. A
89. B
90. D
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