1. An equation representing the reaction of a weak acid with water is
A.
HCl + H2O ⇄ H3O+ + Cl-
B.
NH3 + H2O ⇄ NH4+ + OH-
C.
HCO3- H2O ⇄ H2CO3 + OH-
D.
HCOOH + H2O ⇄ H3O+ + HCOO-
2. The equilibrium expression for the ion product constant of water is
A.
Kw = [H3O+][OH-]
[H2O]
B.
Kw = [H3O+]2[O2]
C.
Kw = [H3O+][OH-]
D.
Kw = [H3O+]2[O2-]
3. Consider the following graph for the titration of 0.1 M NH3 with 1.0 M HCl.
pH
14
I
II
7
III
IV
0
Volume HCl added
A buffer solution is present at point
A.
B.
C.
D.
I
II
III
IV
4. Consider the following equilibrium system for an indicator: HInd + H2O ⇄ H3O+ + IndWhich two species must be of two different colours in order to be used as an indicator?
A.
B.
C.
D.
HInd and H2O
HInd and IndH3O+ and IndHind and H3O+
5. Which of the following indicators is yellow at pH 10.0?
A.
B.
C.
D.
methyl red
phenol red
thymol blue
methyl violet
6. A sample containing 1.20 x 10-2 mole HCl is completely neutralized by 100.0 mL of Sr(OH)2. What is
the [Sr(OH)2]?
A.
B.
C.
D.
6.00 x 10-3 M
6.00 x 10-2 M
1.20 x 10-1 M
2.4 x 10-1 M
7. Which of the following titrations will have the highest pH at the equivalence point?
A.
B.
C.
D.
HBr with NH3
HNO2 with KOH
HCl with Na2CO3
HNO3 with NaOH
8. An Arrhenius acid is defined as a chemical species that
A.
B.
C.
D.
is a proton donor.
is a proton acceptor.
produces hydrogen ions in solution.
produces hydroxide ions in solution.
9. Consider the following acid-base equilibrium system: HC2O4- + H2BO3- ⇄ H3BO3 + C2O42Identify the Bronsted-Lowry bases in this equilibrium.
A.
B.
C.
D.
H2BO3HC2O4HC2O4H2BO3-
and
and
and
and
H3BO3
H3BO3
C2O42C2O42-
10. The equation representing the predominant reaction between NaCH3COO with water is
A.
CHCOO- + H2O ⇄ CH3COOH + OH-
B.
CHCOO- + H2O ⇄ H2O + CH2COO2-
C.
CHCOOH + H2O ⇄ H3O+ + CH3COO-
D.
CHCOOH + H2O ⇄ CH3COOH2+ + OH-
11. Which of the following solutions will have the lowest electrical conductivity?
A.
B.
C.
D.
0.10 M HF
0.10 M NaF
0.10 M H2SO3
0.10 M NaHSO3
12. Which of the following is the strongest Bronsted-Lowry base?
A.
B.
C.
D.
NH3
CO32HSO3H2BO3-
13. A 1.0 x 10-4 M solution has a pH of 10.00. The solute is a
A.
B.
C.
D.
weak acid
weak base
strong acid]
strong base
14. The ionization of water at room temperature is represented by
A.
H2O ⇄ 2H+ + O2-
B.
2H2O ⇄ 2H2 + O2
C.
2H2O ⇄ H2 + 2OH-
D.
2H2O ⇄ 2H3O+ + OH-
15. Addition of HCl to water causes
A.
B.
C.
D.
both [H3O+] and [OH-] to increase
both [H3O+] and [OH-] to decrease
[H3O+] to increase and [OH-] to decrease
[H3O+] to decrease and [OH-] to increase
16. Consider the following:
I.
II.
III.
H2SO4
HSO4SO42-
Which of the above is/are present in a reagent bottle labeled 1.0 M H2SO4?
A.
B.
C.
D.
I only
I and II only
II and III only
I, II, and III
17. The pH of 0.10 M KOH solution is
A.
B.
C.
D.
0.10
1.00
13.00
14.10
18. An indicator changes colour in the pH range 9.0 to 11.0. What is the value of the Ka for the indicator?
A.
B.
C.
D.
1
1
1
1
x
x
x
x
10-13
10-10
10-7
10-1
19. Which of the following are amphiprotic in aqueous solution?
I.
II.
III.
IV.
HBr
H 2O
HCO3H 2C 6H 5O 7-
A
B.
C.
D.
I and II only
II and IV only
II, III, and IV only
I, II, III, and IV
20. Which of the following always applies at the transition point for the indicator Hind?
A.
B.
C.
D.
[Ind-] = [OH-]
[HInd] = [Ind-]
[Ind-] = [H3O+]
[HInd] = [H3O+]
21. Calculate the [H3O+] of a solution prepared by adding 10.0 mL of 2.0 M HCl to 10.0 mL of 1.0 M
NaOH.
A.
0.20 M
B.
0.50 M
C.
1.0 M
D.
2.0 M
22. Both acidic and basic solutions
A.
taste sour
B.
feel slippery
C.
conduct electricity
D.
turn blue litmus red
23. The conjugate acid of HPO42- is
A.
B.
C.
D.
PO43H2PO4H2PO42H2PO43-
24. What is the value of the Kw at 25 oC?
A.,
B.
C.
D.
1.0 x 10-14
1.0 x 10-7
7
14
25. Consider the following equilibrium: 2H2O(l) ⇄ H3O+(aq) + OH-(aq)
A small amount of Fe(H2O)63+ is added to water and equilibrium is re-established. Which of the following
represents the changes in ion concentrations?
A.
B.
C.
D.
[H3O+]
[OH-]
increases
increases
increases
increases
decreases
decreases
decreases
decreases
26. Consider the following equilibrium for an indicator: HInd + H2O ⇄ H3O+ + IndIn a solution of pH of 6.8, the colour of bromthymol blue is
A.
B.
C.
D.
blue because [HInd] = [Ind-]
green because [HInd] = [Ind-]
green because [HInd] < [Ind-]
yellow because [HInd] > [Ind-]
27. The indicator with Ka = 4 x 10-8 is
A.
B.
C.
D.
neutral red
methyl red
indigo carmine
phenolphthalein
28. In a titration a 25.00 mL sample of Sr(OH)2 is completely neutralized by 28.60 mL of 0.100 M HCl.
The concentration of the Sr(OH)2 is
A.
B.
C.
D.
1.43
2.86
5.72
1.14
x
x
x
x
10-3 M
10-3 M
10-2 M
10-1 M
29. A student mixes 15.0 mL of 0.100 M NaOH with 10.0 mL of 0.200 M HCl. The resulting solution is
A.
B.
C.
D.
basic
acidic
neutral
amphiprotic
30. Which of the following salts will dissolve in water to produce a neutral solution?
A.
B.
C.
D.
LiF
CrCl3
KNO3
NH4Cl
31. What is the value of the Kb for HC6H5O72-?
A.
B.
C.
D.
5.9
2.4
4.1
1.7
x
x
x
x
10-10
10-8
10-7
10-5
32. The pOH of 0.015 M HCl solution is
A.
B.
C.
D.
0.97
1.80
12.18
13.03
33. Which of the following will produce an acidic solution?
A.
B.
C.
D.
NaCl
NH4NO3
Ca(NO3)2
Ba(NO3)2
34. Which of the following salts will dissolve in water to produce an acid solution?
A.
B.
C.
D.
LiF
CrCl3
KNO3
NaCl
35. Which of the following salts will dissolve in water to produce a basic solution?
A.
B.
C.
D.
LiF
CrCl3
KNO3
NH4Cl
36. A student mixes 400 mL of 0.100 M NaOH with 100 mL of 0.200 M H2SO4. The resulting solution has
a pH of
A.
14.000
B.
0.000
C.
13.800
D.
7.000
37. A student mixes 500 mL of 0.400 M NaOH with 500 mL of 0.100 M H2SO4. The resulting solution has
a pH of
A.
B.
C.
D.
14.000
0.000
13.000
7.000
38. The strongest acid in water is
A.
B.
C.
D.
HClO4
HI
HF
H 3O +
39. The formula that has the highest pH in water is
A.
B.
C.
D.
HF
H2CO3
H 2C 2O 4
HCN
39. The formula that has the highest pH in water is
A.
B.
C.
D.
NaF
NaCl
H 2C 2O 4
NaCN
1. A chemist prepares a solution by dissolving the salt NaCN in water.
a) Write the equation for the dissociation reaction that occurs.
b) Write the equation for the hydrolysis reaction that occurs.
c) Calculate the value of the equilibrium constant for the hydrolysis
2. A 3.50 x 10-3 M sample of unknown acid, HA has a pH of 2.90. Calculate the value of the Ka and
identify this acid.
3. Calculate the mass of NaOH needed to prepare 2.0 L of a solution with a pH of 12.00.
4. A 1.00 M OCl- solution has an [OH-] of 5.75 x 10-4 M. Calculate the Kb for OCl-.
5. Calculate the pH of a solution prepared by adding 15.0 mL of 0.500 M H2SO4 to 35.0 mL of 0.750 M
NaOH.
6. Determine the pH of a 0.10 M solution of hydrogen cyanide.
7. Determine the pH of 0.100 M NH3.
8. Determine the pH of a saturated solution of Mg(OH)2.
Answers
1. An equation representing the reaction of a weak acid with water is
A.
HCl + H2O ⇄ H3O+ + Cl-
B.
NH3 + H2O ⇄ NH4+ + OH-
C.
HCO3- H2O ⇄ H2CO3 + OH-
D.
HCOOH + H2O ⇄ H3O+ + HCOO-
2. The equilibrium expression for the ion product constant of water is
A.
Kw = [H3O+][OH-]
[H2O]
B.
Kw = [H3O+]2[O2]
C.
Kw = [H3O+][OH-]
D.
Kw = [H3O+]2[O2-]
3. Consider the following graph for the titration of 0.1 M NH3 with 1.0 M HCl.
pH
14
I
II
7
III
IV
0
Volume HCl added
A buffer solution is present at point
A.
B.
C.
D.
I
II
III
IV
4. Consider the following equilibrium system for an indicator: HInd + H2O ⇄ H3O+ + IndWhich two species must be of two different colours in order to be used as an indicator?
A.
B.
C.
D.
HInd and H2O
HInd and IndH3O+ and IndHind and H3O+
5. Which of the following indicators is yellow at pH 10.0?
A.
B.
C.
D.
methyl red
phenol red
thymol blue
methyl violet
6. A sample containing 1.20 x 10-2 mole HCl is completely neutralized by 100.0 mL of Sr(OH)2. What is
the [Sr(OH)2]?
A.
B.
C.
D.
6.00 x 10-3 M
6.00 x 10-2 M
1.20 x 10-1 M
2.4 x 10-1 M
7. Which of the following titrations will have the highest pH at the equivalence point?
A.
B.
C.
D.
HBr with NH3
HNO2 with KOH
HCl with Na2CO3
HNO3 with NaOH
8. An Arrhenius acid is defined as a chemical species that
A.
B.
C.
D.
is a proton donor.
is a proton acceptor.
produces hydrogen ions in solution.
produces hydroxide ions in solution.
9. Consider the following acid-base equilibrium system: HC2O4- + H2BO3- ⇄ H3BO3 + C2O42Identify the Bronsted-Lowry bases in this equilibrium.
A.
B.
C.
D.
H2BO3HC2O4HC2O4H2BO3-
and
and
and
and
H3BO3
H3BO3
C2O42C2O42-
10. The equation representing the predominant reaction between NaCH3COO with water is
A.
CH3COO- + H2O ⇄ CH3COOH + OH-
B.
CH3COO- + H2O ⇄ H2O + CH2COO2-
C.
CH3COOH + H2O ⇄ H3O+ + CH3COO-
D.
CH3COOH + H2O ⇄ CH3COOH2+ + OH-
11. Which of the following solutions will have the lowest electrical conductivity?
A.
B.
C.
D.
0.10 M HF
0.10 M NaF
0.10 M H2SO3
0.10 M NaHSO3
12. Which of the following is the strongest Bronsted-Lowry base?
A.
B.
C.
D.
NH3
CO32HSO3H2BO3-
13. A 1.0 x 10-4 M solution has a pH of 10.00. The solute is a
A.
B.
C.
D.
weak acid
weak base
strong acid]
strong base
14. The ionization of water at room temperature is represented by
A.
H2O ⇄ 2H+ + O2-
B.
2H2O ⇄ 2H2 + O2
C.
2H2O ⇄ H2 + 2OH-
D.
2H2O ⇄ 2H3O+ + OH-
15. Addition of HCl to water causes
A.
B.
C.
D.
both [H3O+] and [OH-] to increase
both [H3O+] and [OH-] to decrease
[H3O+] to increase and [OH-] to decrease
[H3O+] to decrease and [OH-] to increase
16. Consider the following:
I.
II.
III.
H2SO4
HSO4SO42-
Which of the above is/are present in a reagent bottle labeled 1.0 M H2SO4?
A.
B.
C.
D.
I only
I and II only
II and III only
I, II, and III
17. The pH of 0.10 M KOH solution is
A.
B.
C.
D.
0.10
1.00
13.00
14.10
18. An indicator changes colour in the pH range 9.0 to 11.0. What is the value of the Ka for the indicator?
A.
B.
C.
D.
1
1
1
1
x
x
x
x
10-13
10-10
10-7
10-1
19. Which of the following are amphiprotic in aqueous solution?
I.
II.
III.
IV.
HBr
H 2O
HCO3H 2C 6H 5O 7-
A
B.
C.
D.
I and II only
II and IV only
II, III, and IV only
I, II, III, and IV
20. Which of the following always applies at the transition point for the indicator Hind?
A.
B.
C.
D.
[Ind-] = [OH-]
[HInd] = [Ind-]
[Ind-] = [H3O+]
[HInd] = [H3O+]
21. Calculate the [H3O+] of a solution prepared by adding 10.0 mL of 2.0 M HCl to 10.0 mL of 1.0 M
NaOH.
A.
0.20 M
B.
0.50 M
C.
1.0 M
D.
2.0 M
22. Both acidic and basic solutions
A.
taste sour
B.
feel slippery
C.
conduct electricity
D.
turn blue litmus red
23. The conjugate acid of HPO42- is
A.
B.
C.
D.
PO43H2PO4H2PO42H2PO43-
24. What is the value of the Kw at 25 oC?
A.,
B.
C.
D.
1.0 x 10-14
1.0 x 10-7
7
14
25. Consider the following equilibrium: 2H2O(l) ⇄ H3O+(aq) + OH-(aq)
A small amount of Fe(H2O)63+ is added to water and equilibrium is re-established. Which of the following
represents the changes in ion concentrations?
A.
B.
C.
D.
[H3O+]
[OH-]
increases
increases
decreases
decreases
increases
decreases
decreases
increases
26. Consider the following equilibrium for an indicator: HInd + H2O ⇄ H3O+ + IndIn a solution of pH of 6.8, the colour of bromthymol blue is
A.
B.
C.
D.
blue because [HInd] = [Ind-]
green because [HInd] = [Ind-]
green because [HInd] < [Ind-]
yellow because [HInd] > [Ind-]
27. The indicator with Ka = 4 x 10-8 is
A.
B.
C.
D.
neutral red
methyl red
indigo carmine
phenolphthalein
28. In a titration a 25.00 mL sample of Sr(OH)2 is completely neutralized by 28.60 mL of 0.100 M HCl.
The concentration of the Sr(OH)2 is
A.
B.
C.
D.
1.43
2.86
5.72
1.14
x
x
x
x
10-3 M
10-3 M
10-2 M
10-1 M
29. A student mixes 15.0 mL of 0.100 M NaOH with 10.0 mL of 0.200 M HCl. The resulting solution is
A.
B.
C.
D.
basic
acidic
neutral
amphiprotic
30. Which of the following salts will dissolve in water to produce a neutral solution?
A.
B.
C.
D.
LiF
CrCl3
KNO3
NH4Cl
31. What is the value of the Kb for HC6H5O72-?
A.
B.
C.
D.
5.9
2.4
4.1
1.7
x
x
x
x
10-10
10-8
10-7
10-5
32. The pOH of 0.015 M HCl solution is
A.
B.
C.
D.
0.97
1.80
12.18
13.03
33. Which of the following will produce an acidic solution?
A.
B.
C.
D.
NaCl
NH4NO3
Ca(NO3)2
Ba(NO3)2
34. Which of the following salts will dissolve in water to produce an acid solution?
A.
B.
C.
D.
LiF
CrCl3
KNO3
NaCl
35. Which of the following salts will dissolve in water to produce a basic solution?
A.
B.
C.
D.
LiF
CrCl3
KNO3
NH4Cl
36. A student mixes 400 mL of 0.100 M NaOH with 100 mL of 0.200 M H2SO4. The resulting solution has
a pH of
A.
14.000
B.
0.000
C.
13.800
D.
7.000
37. A student mixes 500 mL of 0.400 M NaOH with 500 mL of 0.100 M H2SO4. The resulting solution has
a pH of
A.
B.
C.
D.
14.000
0.000
13.000
7.000
38. The strongest acid in water is
A.
B.
C.
D.
HClO4
HI
HF
H 3O +
39. The formula that has the highest pH in water is
A.
B.
C.
D.
HF
H2CO3
H 2C 2O 4
HCN
39. The formula that has the highest pH in water is
A.
B.
C.
D.
NaF
NaCl
H 2C 2O 4
NaCN
1. A chemist prepares a solution by dissolving the salt NaCN in water.
a) Write the equation for the dissociation reaction that occurs.
Na+
NaCN →
+
CN-
b) Write the equation for the hydrolysis reaction that occurs.
CN-
+
⇄ HCN
H 2O
OH-
+
c) Calculate the value of the equilibrium constant for the hydrolysis
Kb(CN-)
=
1.0 x 10-14
4.9 x 10-10
=
Kw
Ka(HCN)
=
2.0 x 10-5
2. A 3.50 x 10-3 M sample of unknown acid, HA has a pH of 2.90. Calculate the value of the Ka and
identify this acid.
[H+] = 10-pH
= 10-2.90
HA
⇄
=
0.00126 M
H+
+
A-
I
0.00350 M
0
0
C
0.00126 M
0.00126 M
0.00126 M
E
0.00224 M
0.00126 M
0.00126 M
Ka
=
(0.00126)2
0.00224
7.1 x 10-4
=
Citric acid
3. Calculate the mass of NaOH needed to prepare 2.0 L of a solution with a pH of 12.00.
pOH
=
[OH-] = 10-2.00
2.0 L
x
14.00 - 12.00
=
=
2.00
=
0.80 g NaOH
0.010 M
0.010 mol
L
x
40.0 g
mole
4. A 1.00 M OCl- solution has an [OH-] of 5.75 x 10-4 M. Calculate the Kb for OCl-.
OCl-
+
H 2O
⇄
HOCl
+
OH-
I
1.00 M
0
0
C
0.000575 M
0.000575 M
0.000575 M
E
0.9994 M
0.000575 M
0.000575 M
Kb
=
(0.000575)2 =
0.9994
3.31 x 10-7
5. Calculate the pH of a solution prepared by adding 15.0 mL of 0.500 M H2SO4 to 35.0 mL of 0.750 M
NaOH.
H2SO4
+
2H2O
+
2NaOH
→
0.0150 L x 0.500 moles = 0.00750 moles 0.0350 L x 0.750 moles = 0.02625 moles
L
L
I
0.0075 moles
0.02625 moles
C
0.0075 mole
0.0150 moles
E
0
0.01125 mole
[NaOH]
= 0.01125 moles
0.0500 L
=
0.225 M
pH = 13.354
6. Determine the pH of a 0.10 M solution of hydrogen cyanide.
HCN
⇄
H+
+
CN-
I
0.10 M
0
0
C
x
x
x
E
0.10 - x
x
x
Na2SO4
small Ka approximation x = 0
Ka
=
x2
0.10
=
x = 7.0 x 10-6
4.9 x 10-10
pH = 5.15
7. Determine the pH of 0.100 M NH3.
NH3
+
H 2O
⇄
NH4+
+
OH-
I
1.00 M
0
0
C
x
x
x
E
1.00 - x
x
x
small Kb approximation x = 0
Kb(NH3)
Kb
=
=
1.0 x 10-14
5.6 x 10-10
=
Kw
Ka(NH4+)
x2
0.100
=
x = 4.22 x 10-4
=
1.786 x 10-5
1.786 x 10-5
pH = 11.13
8. Determine the pH of a saturated solution of Mg(OH)2.
Mg(OH)2
⇄
x
4x3
Mg2+
x
=
5.6
+
2OH2x
x 10-12
[OH-] = 2x = 2.24 x 10-4
pOH = 3.65
pH = 10.35