Question 1

When 14.7 mL of aqueous HBr (a strong acid) was added to water, 0.482 L of a solution with a pH of 4.23 was produced. What was the molarity of the original HBr solution?

Accepted Answer

A)  1.9 * 10¯3 M 
B)  140 M 
C)  0.288 M 
D)  0.13 M 
E)  None of these choices is correct. 
A)  1.9 * 10¯3 M 
B)  140 M 
C)  0.288 M 
D)  0.13 M 
E)  None of these choices is correct.

Question 2

Which of the following is the strongest acid?

Accepted Answer

A)  CH3COOH 
B)  HF 
C)  H3PO4 
D)  H2SO3 
E)  HI 
A)  CH3COOH 
B)  HF 
C)  H3PO4 
D)  H2SO3 
E)  HI

Question 3

What is the pH of a 0.050 M triethylamine, (C2H5)3N, solution? Kb for triethylamine is 5.3 *10¯4.

Accepted Answer

A)  11.69 
B)  8.68 
C)  5.32 
D)  2.31 
E)  < 2.0 
A)  11.69 
B)  8.68 
C)  5.32 
D)  2.31 
E)  < 2.0

Question 4

Phosphoric acid, H3PO4, is a triprotic acid, for which Ka1 = 7.2 * 10¯3, Ka2 = 6.3 * 10¯8 and Ka3 = 4.2 * 10¯13. What is the value of Kb for the hydrogen phosphate anion, HPO42¯?

Accepted Answer

A)  6.3 * 10¯8 
B)  4.2 * 10¯13 
C)  1.4 * 10¯12 
D)  1.6 * 10¯7 
E)  2.4 * 10¯2 
A)  6.3 * 10¯8 
B)  4.2 * 10¯13 
C)  1.4 * 10¯12 
D)  1.6 * 10¯7 
E)  2.4 * 10¯2

Question 5

Select the correct relationship among the concentrations of species present in a 1.0 M aqueous solution of the weak acid represented by HA.

Accepted Answer

A)  [H2O] > [A¯] ~ [H3O+] > [HA] > [OH¯] 
B)  [H2O] > [HA] > [A¯] > [H3O+] > [OH¯] 
C)  [HA] > [H2O] > [A¯] > [H3O+] > [OH¯] 
D)  [H2O] > [HA] > [A¯] ~ [H3O+] > [OH¯] 
E)  [HA] > [H2O] > [A¯] ~ [H3O+] > [OH¯] 
A)  [H2O] > [A¯] ~ [H3O+] > [HA] > [OH¯] 
B)  [H2O] > [HA] > [A¯] > [H3O+] > [OH¯] 
C)  [HA] > [H2O] > [A¯] > [H3O+] > [OH¯] 
D)  [H2O] > [HA] > [A¯] ~ [H3O+] > [OH¯] 
E)  [HA] > [H2O] > [A¯] ~ [H3O+] > [OH¯]

Question 6

The pH of a 0.200 M solution of the weak base pyridine, C5H5N, is 8.59.
A) Draw up a reaction table for the reaction of 0.200 M pyridine with water
B) Calculate Kb.

Accepted Answer

Question 7

What is the pH of a 0.0035 M KOH solution?

Accepted Answer

A)  2.46 
B)  5.65 
C)  8.35 
D)  11.54 
E)  None of these choices is correct. 
A)  2.46 
B)  5.65 
C)  8.35 
D)  11.54 
E)  None of these choices is correct.

Question 8

Formic acid, HCOOH, is a weak acid with a pKa of 3.74.
A) Draw a reaction table for the reaction of 0.300 M formic acid with water.
B) Calculate the pH of this solution.

Accepted Answer

a. @#IMG-DLM& b. Assuming 0.30

Question 9

The strongest base which can exist in water is the hydroxide ion.

Accepted Answer

A) True 
 B)False

Question 10

A solution is prepared by adding 0.10 mol of sodium fluoride, NaF, to 1.00 L of water. Which statement about the solution is correct?

Accepted Answer

A)  The solution is basic. 
B)  The solution is neutral. 
C)  The solution is acidic. 
D)  The concentrations of fluoride ions and sodium ions will be identical. 
E)  The concentration of fluoride ions will be greater than the concentration of sodium ions. 
A)  The solution is basic. 
B)  The solution is neutral. 
C)  The solution is acidic. 
D)  The concentrations of fluoride ions and sodium ions will be identical. 
E)  The concentration of fluoride ions will be greater than the concentration of sodium ions.

Question 11

The acid dissociation constant Ka equals 1.26 *10¯2 for HSO4¯ and is 5.6 *10¯10 for NH4+. Which statement about the following equilibrium is correct?

Accepted Answer

A)  The reactants will be favored because ammonia is a stronger base than the sulfate anion. 
B)  The products will be favored because the hydrogen sulfate ion is a stronger acid than the ammonium ion. 
C)  Neither reactants nor products will be favored because all of the species are weak acids or bases. 
D)  The initial concentrations of the hydrogen sulfate ion and ammonia must be known before any prediction can be made. 
E)  This reaction is impossible to predict, since the strong acid and the weak base appear on the same side of the equation. 
A)  The reactants will be favored because ammonia is a stronger base than the sulfate anion. 
B)  The products will be favored because the hydrogen sulfate ion is a stronger acid than the ammonium ion. 
C)  Neither reactants nor products will be favored because all of the species are weak acids or bases. 
D)  The initial concentrations of the hydrogen sulfate ion and ammonia must be known before any prediction can be made. 
E)  This reaction is impossible to predict, since the strong acid and the weak base appear on the same side of the equation.

Question 12

According to Brønsted and Lowry, which one of the following is not a conjugate acid-base pair?

Accepted Answer

A)  H3O+, OH¯ 
B)  CH3OH2+, CH3OH 
C)  HI, I¯ 
D)  HSO4¯, SO42¯ 
E)  H2, H¯ 
A)  H3O+, OH¯ 
B)  CH3OH2+, CH3OH 
C)  HI, I¯ 
D)  HSO4¯, SO42¯ 
E)  H2, H¯

Question 13

A solution is prepared by adding 0.10 mol of lithium nitrate, LiNO3, to 1.00 L of water. Which statement about the solution is correct?

Accepted Answer

A)  The solution is basic. 
B)  The solution is neutral. 
C)  The solution is weakly acidic. 
D)  The solution is strongly acidic. 
E)  The values for Ka and Kb for the species in solution must be known before a prediction can be made. 
A)  The solution is basic. 
B)  The solution is neutral. 
C)  The solution is weakly acidic. 
D)  The solution is strongly acidic. 
E)  The values for Ka and Kb for the species in solution must be known before a prediction can be made.

Question 14

It is not possible to have a pH lying outside the range 0 to 14.

Accepted Answer

A) True 
 B)False

Question 15

Which of the following liquids contains the strongest acid?

Accepted Answer

A)  0.1 M HA, pH = 6.85 
B)  0.1 M HD, pH = 7.22 
C)  0.1 M HE, pH = 8.34 
D)  0.1 M HJ, pH = 11.88 
E)  pure water 
A)  0.1 M HA, pH = 6.85 
B)  0.1 M HD, pH = 7.22 
C)  0.1 M HE, pH = 8.34 
D)  0.1 M HJ, pH = 11.88 
E)  pure water

Question 16

Hydrated metal ions in aqueous solution can act as Brønsted-Lowry acids.

Accepted Answer

A) True 
 B)False

Question 17

What is the pH of a 0.00200 M HClO4 solution?

Accepted Answer

A)  0.995 
B)  1.378 
C)  2.699 
D)  6.215 
E)  None of these choices is correct. 
A)  0.995 
B)  1.378 
C)  2.699 
D)  6.215 
E)  None of these choices is correct.

Question 18

A 0.050 M solution of the weak acid HA has [H3O+] = 3.77 * 10¯4 M. What is the Ka for the acid?

Accepted Answer

A)  7.5 * 10¯3 M 
B)  2.8 *10¯6 M 
C)  7.0 * 10¯7 M 
D)  7.0 * 10¯8 M 
E)  2.6 *10¯11 M 
A)  7.5 * 10¯3 M 
B)  2.8 *10¯6 M 
C)  7.0 * 10¯7 M 
D)  7.0 * 10¯8 M 
E)  2.6 *10¯11 M

Question 19

Arsenic acid, H3AsO4, is used industrially to manufacture insecticides. Arsenic acid is a polyprotic acid with K1 = 2.5 * 10¯4, K2 = 5.6 * 10¯8, and K3 = 3 *10¯13. What is the concentration of the HAsO42¯ in a solution whose initial arsenic acid concentration was 0.35 M ?

Accepted Answer

A)  9.4 *10¯3 M 
B)  2.5 * 10¯4 M 
C)  8.8 *10¯5 M 
D)  5.6 * 10¯8 M 
E)  None of these choices is correct. 
A)  9.4 *10¯3 M 
B)  2.5 * 10¯4 M 
C)  8.8 *10¯5 M 
D)  5.6 * 10¯8 M 
E)  None of these choices is correct.

Question 20

What is the pOH of a 0.0085 M KOH solution?

Accepted Answer

A)  2.07 
B)  4.77 
C)  9.23 
D)  11.93 
E)  None of these choices is correct. 
A)  2.07 
B)  4.77 
C)  9.23 
D)  11.93 
E)  None of these choices is correct.

Exam 18: Acid-Base Equilibria

When 14.7 mL of aqueous HBr (a strong acid) was added to water, 0.482 L of a solution with a pH of 4.23 was produced. What was the molarity of the original HBr solution?

Which of the following is the strongest acid?

What is the pH of a 0.050 M triethylamine, (C2H5)3N, solution? Kb for triethylamine is 5.3 *10¯4.

Phosphoric acid, H3PO4, is a triprotic acid, for which Ka1 = 7.2 * 10¯3, Ka2 = 6.3 * 10¯8 and Ka3 = 4.2 * 10¯13. What is the value of Kb for the hydrogen phosphate anion, HPO42¯?

Select the correct relationship among the concentrations of species present in a 1.0 M aqueous solution of the weak acid represented by HA.

The pH of a 0.200 M solution of the weak base pyridine, C5H5N, is 8.59. A) Draw up a reaction table for the reaction of 0.200 M pyridine with water B) Calculate Kb.

What is the pH of a 0.0035 M KOH solution?

Formic acid, HCOOH, is a weak acid with a pKa of 3.74. A) Draw a reaction table for the reaction of 0.300 M formic acid with water. B) Calculate the pH of this solution.

The strongest base which can exist in water is the hydroxide ion.

A solution is prepared by adding 0.10 mol of sodium fluoride, NaF, to 1.00 L of water. Which statement about the solution is correct?

The acid dissociation constant Ka equals 1.26 *10¯2 for HSO4¯ and is 5.6 *10¯10 for NH4+. Which statement about the following equilibrium is correct?

According to Brønsted and Lowry, which one of the following is not a conjugate acid-base pair?

A solution is prepared by adding 0.10 mol of lithium nitrate, LiNO3, to 1.00 L of water. Which statement about the solution is correct?

It is not possible to have a pH lying outside the range 0 to 14.

Which of the following liquids contains the strongest acid?

Hydrated metal ions in aqueous solution can act as Brønsted-Lowry acids.

What is the pH of a 0.00200 M HClO4 solution?

A 0.050 M solution of the weak acid HA has [H3O+] = 3.77 * 10¯4 M. What is the Ka for the acid?

Arsenic acid, H3AsO4, is used industrially to manufacture insecticides. Arsenic acid is a polyprotic acid with K1 = 2.5 * 10¯4, K2 = 5.6 * 10¯8, and K3 = 3 *10¯13. What is the concentration of the HAsO42¯ in a solution whose initial arsenic acid concentration was 0.35 M ?

What is the pOH of a 0.0085 M KOH solution?

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

Ionic Equilibria in Aqueous Systems

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

What is the pH of a 0.050 M triethylamine, (C₂H₅)₃N, solution? K_b for triethylamine is 5.3 *10¯⁴.

Phosphoric acid, H₃PO₄, is a triprotic acid, for which K_a1 = 7.2 * 10¯³, K_a2 = 6.3 * 10¯⁸ and K_a3 = 4.2 * 10¯¹³. What is the value of K_b for the hydrogen phosphate anion, HPO₄²¯?

The pH of a 0.200 M solution of the weak base pyridine, C₅H₅N, is 8.59. A) Draw up a reaction table for the reaction of 0.200 M pyridine with water B) Calculate K_b.

Formic acid, HCOOH, is a weak acid with a pK_a of 3.74. A) Draw a reaction table for the reaction of 0.300 M formic acid with water. B) Calculate the pH of this solution.

The acid dissociation constant K_a equals 1.26 10¯² for HSO₄¯ and is 5.6 10¯¹⁰ for NH₄⁺. Which statement about the following equilibrium is correct?

A solution is prepared by adding 0.10 mol of lithium nitrate, LiNO₃, to 1.00 L of water. Which statement about the solution is correct?

What is the pH of a 0.00200 M HClO₄ solution?

A 0.050 M solution of the weak acid HA has [H₃O⁺] = 3.77 * 10¯⁴ M. What is the K_a for the acid?

Arsenic acid, H₃AsO₄, is used industrially to manufacture insecticides. Arsenic acid is a polyprotic acid with K₁ = 2.5 * 10¯⁴, K₂ = 5.6 * 10¯⁸, and K₃ = 3 *10¯¹³. What is the concentration of the HAsO₄²¯ in a solution whose initial arsenic acid concentration was 0.35 M ?