Question 1

For a diprotic acid H2A, the relationship Ka1 > Ka2 is always true.

Accepted Answer

A) True 
 B)False  True

Question 2

Which of the following substances has the greatest solubility in water?

Accepted Answer

A)  PbI2, Ksp = 7.9 *10¯9 
B)  BaF2, Ksp = 1.5 * 10¯6 
C)  Ca(OH)2, Ksp = 6.5 *10¯6 
D)  Zn(IO3)2, Ksp = 3.9 * 10¯6 
E)  Ag2SO4, Ksp = 1.5 *10¯5 
A)  PbI2, Ksp = 7.9 *10¯9 
B)  BaF2, Ksp = 1.5 * 10¯6 
C)  Ca(OH)2, Ksp = 6.5 *10¯6 
D)  Zn(IO3)2, Ksp = 3.9 * 10¯6 
E)  Ag2SO4, Ksp = 1.5 *10¯5 E

Question 3

The solubility of lead(II) chloride is 0.45 g/100 mL of solution. What is the Ksp of PbCl2?

Accepted Answer

A)  4.9 * 10¯2 
B)  1.7 * 10¯5 
C)  8.5 * 10¯6 
D)  4.2 * 10¯6 
E)  6 
A)  4.9 * 10¯2 
B)  1.7 * 10¯5 
C)  8.5 * 10¯6 
D)  4.2 * 10¯6 
E)  6 B

Question 4

When a strong acid is titrated with a strong base, the pH at the equivalence point

Accepted Answer

A)  is greater than 7.0. 
B)  is equal to 7.0. 
C)  is less than 7.0, but is not 3.5. 
D)  is equal to the pKa of the acid. 
E)  is equal to 3.5. 
A)  is greater than 7.0. 
B)  is equal to 7.0. 
C)  is less than 7.0, but is not 3.5. 
D)  is equal to the pKa of the acid. 
E)  is equal to 3.5.

Question 5

Which of the following substances has the greatest solubility in water?

Accepted Answer

A)  Ba(IO3)2, Ksp = 1.5 *10¯9 
B)  PbF2, Ksp = 3.6 *10¯8 
C)  SrSO4, Ksp = 3.2 * 10¯7 
D)  CuCl, Ksp = 1.9 * 10¯7 
E)  CdS, Ksp = 1.0 * 10¯24 
A)  Ba(IO3)2, Ksp = 1.5 *10¯9 
B)  PbF2, Ksp = 3.6 *10¯8 
C)  SrSO4, Ksp = 3.2 * 10¯7 
D)  CuCl, Ksp = 1.9 * 10¯7 
E)  CdS, Ksp = 1.0 * 10¯24

Question 6

Which of the following acids should be used to prepare a buffer with a pH of 4.5?

Accepted Answer

A)  HOC6H4OCOOH, Ka = 1.0 *10¯3 
B)  C6H4(COOH)2, Ka = 2.9 *0 10¯4 
C)  CH3COOH, Ka = 1.8 * 10¯5 
D)  C5H5O5COOH, Ka = 4.0 * 10¯6 
E)  HBrO, Ka = 2.3 * 10¯9 
A)  HOC6H4OCOOH, Ka = 1.0 *10¯3 
B)  C6H4(COOH)2, Ka = 2.9 *0 10¯4 
C)  CH3COOH, Ka = 1.8 * 10¯5 
D)  C5H5O5COOH, Ka = 4.0 * 10¯6 
E)  HBrO, Ka = 2.3 * 10¯9

Question 7

A 20.0-mL sample of 0.30 M HBr is titrated with 0.15 M NaOH. What is the pH of the solution after 40.3 mL of NaOH have been added to the acid?

Accepted Answer

A)  2.95 
B)  3.13 
C)  10.87 
D)  11.05 
E)  13.14 
A)  2.95 
B)  3.13 
C)  10.87 
D)  11.05 
E)  13.14

Question 8

You need to prepare a buffer solution with a pH of 4.00, using NaF and HF. What ratio of the ratio of [base]/[acid] should be used in making the buffer? For HF, Ka = 7.2 * 10¯4

Accepted Answer

A)  [base]/[acid] = 0.14 
B)  [base]/[acid] = 0.42 
C)  [base]/[acid] = 2.36 
D)  [base]/[acid] = 7.20 
E)  None of these choices is correct. 
A)  [base]/[acid] = 0.14 
B)  [base]/[acid] = 0.42 
C)  [base]/[acid] = 2.36 
D)  [base]/[acid] = 7.20 
E)  None of these choices is correct.

Question 9

What is the pH of a solution that consists of 0.50 M H2C6H6O6 (ascorbic acid) and 0.75 M NaHC6H6O6 (sodium ascorbate)? For ascorbic acid, Ka = 6.8 *10¯5

Accepted Answer

A)  3.76 
B)  3.99 
C)  4.34 
D)  4.57 
E)  5.66 
A)  3.76 
B)  3.99 
C)  4.34 
D)  4.57 
E)  5.66

Question 10

A sample of a monoprotic acid (HA) weighing 0.384 g is dissolved in water and the solution is titrated with aqueous NaOH. If 30.0 mL of 0.100 M NaOH is required to reach the equivalence point, what is the molar mass of HA?

Accepted Answer

A)  37.0 g/mol 
B)  81.0 g/mol 
C)  128 g/mol 
D)  20.3 g/mol 
E)  211 g/mol 
A)  37.0 g/mol 
B)  81.0 g/mol 
C)  128 g/mol 
D)  20.3 g/mol 
E)  211 g/mol

Question 11

When a weak acid is titrated with a strong base, the pH at the equivalence point

Accepted Answer

A)  is greater than 7.0. 
B)  is equal to 7.0. 
C)  is less than 7.0. 
D)  is equal to the pKa of the acid. 
E)  is equal to 14.0 - pKb, where pKb is that of the base. 
A)  is greater than 7.0. 
B)  is equal to 7.0. 
C)  is less than 7.0. 
D)  is equal to the pKa of the acid. 
E)  is equal to 14.0 - pKb, where pKb is that of the base.

Question 12

What is the [H3O+] in a solution that consists of 1.2 M HClO and 2.3 M NaClO? Ka = 3.5 *10¯8

Accepted Answer

A)  7.8 * 10¯9 M 
B)  1.8 * 10¯8 M 
C)  6.7 * 10¯8 M 
D)  1.6 *10¯7 M 
E)  None of these choices is correct. 
A)  7.8 * 10¯9 M 
B)  1.8 * 10¯8 M 
C)  6.7 * 10¯8 M 
D)  1.6 *10¯7 M 
E)  None of these choices is correct.

Question 13

Which, if any, of the following aqueous mixtures would be a buffer system?

Accepted Answer

A)  CH3COOH, NaH2PO4 
B)  H2CO3, HCO3¯ 
C)  H2PO4¯, HCO3¯ 
D)  HSO4¯, HSO3¯ 
E)  None of these choices is correct. 
A)  CH3COOH, NaH2PO4 
B)  H2CO3, HCO3¯ 
C)  H2PO4¯, HCO3¯ 
D)  HSO4¯, HSO3¯ 
E)  None of these choices is correct.

Question 14

Calculate the solubility of barium carbonate, BaCO3, in pure water. Ksp = 2.0 *10¯9

Accepted Answer

A)  1.3 * 10¯3 M 
B)  3.2 * 10¯5 M 
C)  2.2 * 10¯5 M 
D)  4.5 *10¯5 M 
E)  4.0 * 10¯18 M 
A)  1.3 * 10¯3 M 
B)  3.2 * 10¯5 M 
C)  2.2 * 10¯5 M 
D)  4.5 *10¯5 M 
E)  4.0 * 10¯18 M

Question 15

Which one of the following pairs of 0.100 mol L¯1 solutions, when mixed, will produce a buffer solution?

Accepted Answer

A)  50. mL of aqueous CH3COOH and 25. mL of aqueous HCl 
B)  50. mL of aqueous CH3COOH and 100. mL of aqueous NaOH 
C)  50. mL of aqueous NaOH and 25. mL of aqueous HCl 
D)  50. mL of aqueous CH3COONa and 25. mL of aqueous NaOH 
E)  50. mL of aqueous CH3COOH and 25. mL of aqueous CH3COONa 
A)  50. mL of aqueous CH3COOH and 25. mL of aqueous HCl 
B)  50. mL of aqueous CH3COOH and 100. mL of aqueous NaOH 
C)  50. mL of aqueous NaOH and 25. mL of aqueous HCl 
D)  50. mL of aqueous CH3COONa and 25. mL of aqueous NaOH 
E)  50. mL of aqueous CH3COOH and 25. mL of aqueous CH3COONa

Question 16

Assuming that the total volume does not change after 0.200 g of KCl is added to 1.0 L of a saturated aqueous solution of AgCl, calculate the number of moles of Ag+ ion in the solution after equilibrium has been reestablished. For AgCl, Ksp = 1.8 *10¯10

Accepted Answer

A)  1.8 * 10¯10 mol Ag+ 
B)  9.0 * 10¯10 mol Ag+ 
C)  9.0 * 10¯9 mol Ag+ 
D)  6.7 *10¯8 mol Ag+ 
E)  1.3 *10¯5 mol Ag+ 
A)  1.8 * 10¯10 mol Ag+ 
B)  9.0 * 10¯10 mol Ag+ 
C)  9.0 * 10¯9 mol Ag+ 
D)  6.7 *10¯8 mol Ag+ 
E)  1.3 *10¯5 mol Ag+

Question 17

The solubility of magnesium phosphate is 2.27 * 10¯3 g/1.0 L of solution. What is the Ksp for Mg3(PO4)2?

Accepted Answer

A)  6.5 * 10¯12 
B)  6.0 *10¯14 
C)  5.2 *10¯24 
D)  4.8* 10¯26 
E)  1.0 * 10¯26 
A)  6.5 * 10¯12 
B)  6.0 *10¯14 
C)  5.2 *10¯24 
D)  4.8* 10¯26 
E)  1.0 * 10¯26

Question 18

Equal volumes of the following pairs of solutions are mixed. Which pair will produce a buffer solution?

Accepted Answer

A)  0.10 mol L¯1 HCl and 0.05 mol L¯1 NaOH 
B)  0.10 mol L¯1 HCl and 0.15 mol L¯1 NH3 
C)  0.10 mol L¯1 HCl and 0.05 mol L¯1 NH3 
D)  0.10 mol L¯1 HCl and 0.20 mol L¯1 CH3COOH 
E)  0.10 mol L¯1 HCl and 0.20 mol L¯1 NaCl 
A)  0.10 mol L¯1 HCl and 0.05 mol L¯1 NaOH 
B)  0.10 mol L¯1 HCl and 0.15 mol L¯1 NH3 
C)  0.10 mol L¯1 HCl and 0.05 mol L¯1 NH3 
D)  0.10 mol L¯1 HCl and 0.20 mol L¯1 CH3COOH 
E)  0.10 mol L¯1 HCl and 0.20 mol L¯1 NaCl

Question 19

A phosphate buffer (H2PO4¯/HPO42¯) has a pH of 8.3. Which of the following changes will cause the pH to increase?

Accepted Answer

A)  dissolving a small amount of Na2HPO4 
B)  dissolving a small amount of NaH2PO4 
C)  adding a small amount of dilute hydrochloric acid 
D)  adding a small amount of dilute phosphoric acid 
E)  making the buffer more concentrated by removing some water 
A)  dissolving a small amount of Na2HPO4 
B)  dissolving a small amount of NaH2PO4 
C)  adding a small amount of dilute hydrochloric acid 
D)  adding a small amount of dilute phosphoric acid 
E)  making the buffer more concentrated by removing some water

Question 20

When 20.0 mL of 0.15 M hydrochloric acid is mixed with 20.0 mL of 0.10 M sodium hydroxide, the pH of the resulting solution is

Accepted Answer

A)  0.00 
B)  12.40 
C)  1.60 
D)  0.82 
E)  7.00 
A)  0.00 
B)  12.40 
C)  1.60 
D)  0.82 
E)  7.00

Exam 19: Ionic Equilibria in Aqueous Systems

For a diprotic acid H2A, the relationship Ka1 > Ka2 is always true.

Which of the following substances has the greatest solubility in water?

The solubility of lead(II) chloride is 0.45 g/100 mL of solution. What is the Ksp of PbCl2?

When a strong acid is titrated with a strong base, the pH at the equivalence point

Which of the following substances has the greatest solubility in water?

Which of the following acids should be used to prepare a buffer with a pH of 4.5?

A 20.0-mL sample of 0.30 M HBr is titrated with 0.15 M NaOH. What is the pH of the solution after 40.3 mL of NaOH have been added to the acid?

You need to prepare a buffer solution with a pH of 4.00, using NaF and HF. What ratio of the ratio of [base]/[acid] should be used in making the buffer? For HF, Ka = 7.2 * 10¯4

What is the pH of a solution that consists of 0.50 M H2C6H6O6 (ascorbic acid) and 0.75 M NaHC6H6O6 (sodium ascorbate)? For ascorbic acid, Ka = 6.8 *10¯5

A sample of a monoprotic acid (HA) weighing 0.384 g is dissolved in water and the solution is titrated with aqueous NaOH. If 30.0 mL of 0.100 M NaOH is required to reach the equivalence point, what is the molar mass of HA?

When a weak acid is titrated with a strong base, the pH at the equivalence point

What is the [H3O+] in a solution that consists of 1.2 M HClO and 2.3 M NaClO? Ka = 3.5 *10¯8

Which, if any, of the following aqueous mixtures would be a buffer system?

Calculate the solubility of barium carbonate, BaCO3, in pure water. Ksp = 2.0 *10¯9

Which one of the following pairs of 0.100 mol L¯1 solutions, when mixed, will produce a buffer solution?

Assuming that the total volume does not change after 0.200 g of KCl is added to 1.0 L of a saturated aqueous solution of AgCl, calculate the number of moles of Ag+ ion in the solution after equilibrium has been reestablished. For AgCl, Ksp = 1.8 *10¯10

The solubility of magnesium phosphate is 2.27 * 10¯3 g/1.0 L of solution. What is the Ksp for Mg3(PO4)2?

Equal volumes of the following pairs of solutions are mixed. Which pair will produce a buffer solution?

A phosphate buffer (H2PO4¯/HPO42¯) has a pH of 8.3. Which of the following changes will cause the pH to increase?

When 20.0 mL of 0.15 M hydrochloric acid is mixed with 20.0 mL of 0.10 M sodium hydroxide, the pH of the resulting solution is

Keys to the Study of Chemistry

The Components of Matter

Stoichiometry of Formulas and Equations

Three Major Classes of Chemical Reactions

Gases and the Kinetic-Molecular Theory

Thermochemistry: Energy Flow and Chemical Change

Quantum Theory and Atomic Structure

Electron Configuration and Chemical Periodicity

Models of Chemical Bonding

The Shapes of Molecules

Theories of Covalent Bonding

Intermolecular Forces: Liquids, Solids, and Phase Changes

The Properties of Mixtures: Solutions and Colloids

Periodic Patterns in the Main-Group Elements

Organic Compounds and the Atomic Properties of Carbon

Kinetics: Rates and Mechanisms of Chemical Reactions

Equilibrium: the Extent of Chemical Reactions

Acid-Base Equilibria

Thermodynamics: Entropy, Free Energy, and the Direction of Chemical Reactions

Electrochemistry: Chemical Change and Electrical Work

The Elements in Nature and Industry

The Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

For a diprotic acid H₂A, the relationship K_a1 > K_a2 is always true.

The solubility of lead(II) chloride is 0.45 g/100 mL of solution. What is the K_sp of PbCl₂?

You need to prepare a buffer solution with a pH of 4.00, using NaF and HF. What ratio of the ratio of [base]/[acid] should be used in making the buffer? For HF, K_a = 7.2 * 10¯⁴

What is the pH of a solution that consists of 0.50 M H₂C₆H₆O₆ (ascorbic acid) and 0.75 M NaHC₆H₆O₆ (sodium ascorbate)? For ascorbic acid, K_a = 6.8 *10¯⁵

What is the [H₃O⁺] in a solution that consists of 1.2 M HClO and 2.3 M NaClO? K_a = 3.5 *10¯⁸

Calculate the solubility of barium carbonate, BaCO₃, in pure water. K_sp = 2.0 *10¯⁹

Which one of the following pairs of 0.100 mol L¯¹ solutions, when mixed, will produce a buffer solution?

Assuming that the total volume does not change after 0.200 g of KCl is added to 1.0 L of a saturated aqueous solution of AgCl, calculate the number of moles of Ag⁺ ion in the solution after equilibrium has been reestablished. For AgCl, K_sp = 1.8 *10¯¹⁰

The solubility of magnesium phosphate is 2.27 * 10¯³ g/1.0 L of solution. What is the K_sp for Mg₃(PO₄)₂?

A phosphate buffer (H₂PO₄¯/HPO₄²¯) has a pH of 8.3. Which of the following changes will cause the pH to increase?