Question 1

What is the pH of a 0.30 M trisodium phosphate solution? [Ka for monohydrogen phosphate ion is 4.2 × 10-13]

Accepted Answer

A)  13.3 
B)  12.9 
C)  10.5 
D)  9.8 
E)  8.6 
A)  13.3 
B)  12.9 
C)  10.5 
D)  9.8 
E)  8.6

Question 2

For HClO2, Ka = 1.2 × 10-2. What is the pH of a solution in which [NaClO2] = 0.193 M and [HClO2] = 0.203 M?

Accepted Answer

A)  3.32 
B)  0.11 
C)  1.92 
D)  1.94 
E)  1.90 
A)  3.32 
B)  0.11 
C)  1.92 
D)  1.94 
E)  1.90

Question 3

In 0.100 M HC2H3O2(aq), [H3O+(aq)] = [C2H3O2-(aq)] = 1.3 x 10-3 M. If a few drops of concentrated HCl(aq) are added to this solution, the C2H3O2-(aq) concentration is:

Accepted Answer

A)  -3 M 
B)  > 1.3 x 10-3 M 
C)  = 1.3 x 10-3 M 
D)  0.100 M 
A)  -3 M 
B)  > 1.3 x 10-3 M 
C)  = 1.3 x 10-3 M 
D)  0.100 M

Question 4

In the titration of 50.0 mL of 0.0200 M C6H5COOH(aq) with 0.100 M NaOH(aq), what is/are the major species in the solution after the addition of 5.0 mL of NaOH(aq)?

Accepted Answer

A)  C6H5COOH, C6H5COO-, and Na+ 
B)  C6H5COOH 
C)  C6H5COO- and Na+ 
D)  C6H5COOH, OH-, and Na+ 
A)  C6H5COOH, C6H5COO-, and Na+ 
B)  C6H5COOH 
C)  C6H5COO- and Na+ 
D)  C6H5COOH, OH-, and Na+

Question 5

A weak acid has Ka = 4.2 × 10-3. If [A-] = 2.0 M, what must [HA] be so that [H+] = 2.1 × 10-3 M?

Accepted Answer

A)  1.5 M 
B)  2.0 M 
C)  1.0 M 
D)  0.5 M 
E)  0.25 M 
A)  1.5 M 
B)  2.0 M 
C)  1.0 M 
D)  0.5 M 
E)  0.25 M

Question 6

What mass of sodium acetate should be dissolved in 250.0 mL of 0.30 M acetic acid to form a buffer of pH 5.0? [Ka for acetic acid is 1.8 × 10-5]

Accepted Answer

A)  11 g 
B)  8.0 g 
C)  7.5 g 
D)  5.0 g 
E)  1.4 g 
A)  11 g 
B)  8.0 g 
C)  7.5 g 
D)  5.0 g 
E)  1.4 g

Question 7

Which of the following can act as buffer solutions? 
I. 0.1 M HC2H3O2/0.1 M NaC2H3O2
II. 0.1 M NH3/0.1 M NH4Cl
III. 0.1 M HNO3/0.1 M NaNO3
IV. 0.1 M H2SO3/0.1 M NaHSO3
V. 0.1 M KHSO4/ 0.1 M H2SO4

Accepted Answer

A)  I), II), and III) 
B)  II), III) and IV) 
C)  III) and IV) 
D)  I), II) and IV) 
E)  III), IV) and V) 
A)  I), II), and III) 
B)  II), III) and IV) 
C)  III) and IV) 
D)  I), II) and IV) 
E)  III), IV) and V)

Question 8

What is the pH of a buffer that is 0.88 M HCN(aq) and 0.53 M NaCN(aq)? The Ka of HCN is 6.2 x 10-10.

Accepted Answer

A)  8.99 
B)  9.21 
C)  9.43 
D)  4.79 
A)  8.99 
B)  9.21 
C)  9.43 
D)  4.79

Question 9

Determine the [F-] of the following solution. Initial concentrations are given. [HF] = 1.296 M, [NaF] = 1.045 M, Ka for HF is 6.6 × 10-4

Accepted Answer

A)  1.046 M 
B)  2.344 M 
C)  5.3 × 10-4 M 
D)  8.2 × 10-4 M 
E)  0.251 M 
A)  1.046 M 
B)  2.344 M 
C)  5.3 × 10-4 M 
D)  8.2 × 10-4 M 
E)  0.251 M

Question 10

Which condition characterizes the stoichiometric point of a neutralization titration?

Accepted Answer

A)  Equivalent amounts of acid and base have reacted. 
B)  The pH is exactly 7.0. 
C)  The indicator changes color. 
D)  A slight excess of titrant is present. 
E)  A slight excess of indicator is present. 
A)  Equivalent amounts of acid and base have reacted. 
B)  The pH is exactly 7.0. 
C)  The indicator changes color. 
D)  A slight excess of titrant is present. 
E)  A slight excess of indicator is present.

Question 11

What is the concentration of the acetate ion of a solution measured to be 0.20 M acetic acid and 0.20 M in hydrochloric acid? [Ka for acetic acid = 1.8 × 10-5]

Accepted Answer

A)  3.6 × 10-5 M 
B)  9.0 × 10-6 M 
C)  1.8 × 10-5 M 
D)  7.2 × 10-5 M 
E)  0.20 M 
A)  3.6 × 10-5 M 
B)  9.0 × 10-6 M 
C)  1.8 × 10-5 M 
D)  7.2 × 10-5 M 
E)  0.20 M

Question 12

In a solution prepared by mixing equal volumes of 0.20 M acetic acid and 0.20 M hydrobromic acid, the common ion is ________.

Accepted Answer

A)  Br- 
B)  C2H3O22- 
C)  H2C2H3O2 
D)  H2Br+ 
E)  H3O+ 
A)  Br- 
B)  C2H3O22- 
C)  H2C2H3O2 
D)  H2Br+ 
E)  H3O+

Question 13

The following compounds are available as 0.10 M aqueous solutions: pyridine (pKb = 8.82), triethylamine (pKb = 3.25), HClO4, NaOH, phenol (pKa = 9.96), HClO (pKa = 7.54), and NH3 (pKb = 4.74). Identify two solutions that could be used to prepare a buffer with a pH of approximately 5.

Accepted Answer

A)  pyridine and HClO4 
B)  triethyamine and HClO4 
C)  phenol and NaOH 
D)  HClO and NaOH 
A)  pyridine and HClO4 
B)  triethyamine and HClO4 
C)  phenol and NaOH 
D)  HClO and NaOH

Question 14

A solution containing equimolar amounts of a weak acid with Ka = 10-5 and its sodium salt has:

Accepted Answer

A) pH > 7 B) pH < 7 C) pH = 7 D) pH dependent on concentration ratios E) pH dependent on the nature of the acid anion A) pH > 7 B) pH < 7 C) pH = 7 D) pH dependent on concentration ratios E) pH dependent on the nature of the acid anion

Question 15

A weak acid-strong base will produce a longer vertical section of a titration curve than will a strong acid-strong base.

Accepted Answer

A) True 
 B)False

Question 16

A buffer is 0.282 M C6H5COOH(aq) and 0.282 M Na(C6H5COO)(aq). Calculate the pH after the addition of 0.150 moles of nitric acid to 1.0 L of the buffer. For C6H5COOH, pKa = 4.20.

Accepted Answer

A)  3.69 
B)  4.20 
C)  4.71 
D)  3.87 
A)  3.69 
B)  4.20 
C)  4.71 
D)  3.87

Question 17

What is the pH of a buffer solution prepared by dissolving 25.5 g NaC2H3O2 in a sufficient volume of 0.550 M HC2H3O2 to make 500.0 mL of buffer?

Accepted Answer

A)  4.74 
B)  4.68 
C)  4.91 
D)  4.57 
E)  4.79 
A)  4.74 
B)  4.68 
C)  4.91 
D)  4.57 
E)  4.79

Question 18

Determine the pH of the following solution. Initial concentrations are given. [HF] = 1.296 M, [NaF] = 1.045 M, Ka for HF is 6.6 × 10-4

Accepted Answer

A)  10.73 
B)  3.27 
C)  3.18 
D)  3.09 
E)  11.91 
A)  10.73 
B)  3.27 
C)  3.18 
D)  3.09 
E)  11.91

Question 19

What is the change in pH after addition of 10.0 mL of 1.0 M sodium hydroxide to 90.0 mL of a 1.0 M NH3/1.0 M NH4+ buffer? [Kb for ammonia is 1.8 × 10-5]

Accepted Answer

A)  1.0 pH unit 
B)  0.1 pH unit 
C)  0.01 pH unit 
D)  0.001 pH unit 
E)  zero 
A)  1.0 pH unit 
B)  0.1 pH unit 
C)  0.01 pH unit 
D)  0.001 pH unit 
E)  zero

Question 20

What volume in mL of 2.0 M H2SO4 is needed to neutralize 7.8 g of Al(OH)3(78.0 g/mol)? Al2(SO4)3 and water are the titration products.

Accepted Answer

A)  150 
B)  75 
C)  300 
D)  500 
E)  250 
A)  150 
B)  75 
C)  300 
D)  500 
E)  250

Exam 17: Additional Aspects of Acid-Base Equilibria

What is the pH of a 0.30 M trisodium phosphate solution? [Ka for monohydrogen phosphate ion is 4.2 × 10-13]

For HClO2, Ka = 1.2 × 10-2. What is the pH of a solution in which [NaClO2] = 0.193 M and [HClO2] = 0.203 M?

In 0.100 M HC2H3O2(aq), [H3O+(aq)] = [C2H3O2-(aq)] = 1.3 x 10-3 M. If a few drops of concentrated HCl(aq) are added to this solution, the C2H3O2-(aq) concentration is:

In the titration of 50.0 mL of 0.0200 M C6H5COOH(aq) with 0.100 M NaOH(aq), what is/are the major species in the solution after the addition of 5.0 mL of NaOH(aq)?

A weak acid has Ka = 4.2 × 10-3. If [A-] = 2.0 M, what must [HA] be so that [H+] = 2.1 × 10-3 M?

What mass of sodium acetate should be dissolved in 250.0 mL of 0.30 M acetic acid to form a buffer of pH 5.0? [Ka for acetic acid is 1.8 × 10-5]

Which of the following can act as buffer solutions? I. 0.1 M HC2H3O2/0.1 M NaC2H3O2 II. 0.1 M NH3/0.1 M NH4Cl III. 0.1 M HNO3/0.1 M NaNO3 IV. 0.1 M H2SO3/0.1 M NaHSO3 V. 0.1 M KHSO4/ 0.1 M H2SO4

What is the pH of a buffer that is 0.88 M HCN(aq) and 0.53 M NaCN(aq)? The Ka of HCN is 6.2 x 10-10.

Determine the [F-] of the following solution. Initial concentrations are given. [HF] = 1.296 M, [NaF] = 1.045 M, Ka for HF is 6.6 × 10-4

Which condition characterizes the stoichiometric point of a neutralization titration?

What is the concentration of the acetate ion of a solution measured to be 0.20 M acetic acid and 0.20 M in hydrochloric acid? [Ka for acetic acid = 1.8 × 10-5]

In a solution prepared by mixing equal volumes of 0.20 M acetic acid and 0.20 M hydrobromic acid, the common ion is ________.

The following compounds are available as 0.10 M aqueous solutions: pyridine (pKb = 8.82), triethylamine (pKb = 3.25), HClO4, NaOH, phenol (pKa = 9.96), HClO (pKa = 7.54), and NH3 (pKb = 4.74). Identify two solutions that could be used to prepare a buffer with a pH of approximately 5.

A solution containing equimolar amounts of a weak acid with Ka = 10-5 and its sodium salt has:

A weak acid-strong base will produce a longer vertical section of a titration curve than will a strong acid-strong base.

A buffer is 0.282 M C6H5COOH(aq) and 0.282 M Na(C6H5COO)(aq). Calculate the pH after the addition of 0.150 moles of nitric acid to 1.0 L of the buffer. For C6H5COOH, pKa = 4.20.

What is the pH of a buffer solution prepared by dissolving 25.5 g NaC2H3O2 in a sufficient volume of 0.550 M HC2H3O2 to make 500.0 mL of buffer?

Determine the pH of the following solution. Initial concentrations are given. [HF] = 1.296 M, [NaF] = 1.045 M, Ka for HF is 6.6 × 10-4

What is the change in pH after addition of 10.0 mL of 1.0 M sodium hydroxide to 90.0 mL of a 1.0 M NH3/1.0 M NH4+ buffer? [Kb for ammonia is 1.8 × 10-5]

What volume in mL of 2.0 M H2SO4 is needed to neutralize 7.8 g of Al(OH)3(78.0 g/mol)? Al2(SO4)3 and water are the titration products.

Matter - Its Properties and Measurement

Atoms and the Atomic Theory

Chemical Compounds

Chemical Reactions

Introduction to Reactions in Aqueous Solutions

Gases

Thermochemistry

Electrons in Atoms

The Periodic Table and Some Atomic Properties

Chemical Bonding I: Basic Concepts

Chemical Bonding II: Additional Aspects

Intermolecular Forces: Liquids and Solids

Solutions and Their Physical Properties

Chemical Kinetics

Principles of Chemical Equilibrium

Acids and Bases

Solubility and Complex-Ion Equilibria

Spontaneous Change: Entropy and Free Energy

Electrochemistry

Main Group Elements I: Groups 1, 2, 13, and 14

Main Group Elements II: Groups 18, 17, 16, 15, and Hydrogen

The Transition Elements

Complex Ions and Coordination Compounds

Nuclear Chemistry 1-41

Structures of Organic Compounds

Reactions of Organic Compounds

Chemistry of the Living State

Filters

What is the pH of a 0.30 M trisodium phosphate solution? [Ka for monohydrogen phosphate ion is 4.2 × 10^-13]

For HClO₂, Ka = 1.2 × 10^-2. What is the pH of a solution in which [NaClO₂] = 0.193 M and [HClO₂] = 0.203 M?

In 0.100 M HC₂H₃O₂(aq), [H₃O+(aq)] = [C₂H₃O₂^-(aq)] = 1.3 x 10^-3 M. If a few drops of concentrated HCl(aq) are added to this solution, the C₂H₃O₂^-(aq) concentration is:

In the titration of 50.0 mL of 0.0200 M C₆H₅COOH(aq) with 0.100 M NaOH(aq), what is/are the major species in the solution after the addition of 5.0 mL of NaOH(aq)?

A weak acid has Ka = 4.2 × 10^-3. If [A-] = 2.0 M, what must [HA] be so that [H+] = 2.1 × 10^-3 M?

What mass of sodium acetate should be dissolved in 250.0 mL of 0.30 M acetic acid to form a buffer of pH 5.0? [Ka for acetic acid is 1.8 × 10^-5]

Which of the following can act as buffer solutions? I. 0.1 M HC₂H₃O₂/0.1 M NaC₂H₃O₂ II. 0.1 M NH₃/0.1 M NH₄Cl III. 0.1 M HNO₃/0.1 M NaNO₃ IV. 0.1 M H₂SO₃/0.1 M NaHSO₃ V. 0.1 M KHSO₄/ 0.1 M H₂SO₄

What is the pH of a buffer that is 0.88 M HCN(aq) and 0.53 M NaCN(aq)? The Ka of HCN is 6.2 x 10^-10.

Determine the [F-] of the following solution. Initial concentrations are given. [HF] = 1.296 M, [NaF] = 1.045 M, Ka for HF is 6.6 × 10^-4

What is the concentration of the acetate ion of a solution measured to be 0.20 M acetic acid and 0.20 M in hydrochloric acid? [Ka for acetic acid = 1.8 × 10^-5]

The following compounds are available as 0.10 M aqueous solutions: pyridine (pKb = 8.82), triethylamine (pKb = 3.25), HClO₄, NaOH, phenol (pKa = 9.96), HClO (pKa = 7.54), and NH₃ (pKb = 4.74). Identify two solutions that could be used to prepare a buffer with a pH of approximately 5.

A solution containing equimolar amounts of a weak acid with Ka = 10^-5 and its sodium salt has:

A buffer is 0.282 M C₆H₅COOH(aq) and 0.282 M Na(C₆H₅COO)(aq). Calculate the pH after the addition of 0.150 moles of nitric acid to 1.0 L of the buffer. For C₆H₅COOH, pKa = 4.20.

What is the pH of a buffer solution prepared by dissolving 25.5 g NaC₂H₃O₂ in a sufficient volume of 0.550 M HC₂H₃O₂ to make 500.0 mL of buffer?

Determine the pH of the following solution. Initial concentrations are given. [HF] = 1.296 M, [NaF] = 1.045 M, Ka for HF is 6.6 × 10^-4

What is the change in pH after addition of 10.0 mL of 1.0 M sodium hydroxide to 90.0 mL of a 1.0 M NH₃/1.0 M NH₄⁺ buffer? [Kb for ammonia is 1.8 × 10^-5]

What volume in mL of 2.0 M H₂SO₄ is needed to neutralize 7.8 g of Al(OH)₃(78.0 g/mol)? Al₂(SO₄)₃ and water are the titration products.