Question 1

Calculate [H+] in a 1.2 × 10-5 M solution of NH4Cl. (Kb for NH3 = 1.8 × 10-5)

Accepted Answer

A)  1.5 × 10-5 M 
B)  8.2 × 10-8 M 
C)  1.3 × 10-7 M 
D)  1.2 × 10-5 M 
E)  7.7 × 10-8 M 
A)  1.5 × 10-5 M 
B)  8.2 × 10-8 M 
C)  1.3 × 10-7 M 
D)  1.2 × 10-5 M 
E)  7.7 × 10-8 M

Question 2

Calculate the pH of a 2.0 × 10-5 M solution of HOC6H5. (Ka = 1.6 × 10-10)

Accepted Answer

A)  6.94 
B)  6.75 
C)  7.06 
D)  7.25 
E)  none of these 
A)  6.94 
B)  6.75 
C)  7.06 
D)  7.25 
E)  none of these

Question 3

A 0.050 M aqueous solution of a weak monoprotic acid is 1.2% ionized at equilibrium at 25° C. Calculate Ka for this acid.

Accepted Answer

A)  7.3 × 10-33 
B)  29 
C)  3.4 × 10-2 
D)  6.4 × 10-8 
E)  none of these 
A)  7.3 × 10-33 
B)  29 
C)  3.4 × 10-2 
D)  6.4 × 10-8 
E)  none of these

Question 4

Which of the following indicates the most acidic solution?

Accepted Answer

A)  pOH = 5.9 
B)  [H+] = 0.3 M 
C)  [H+] = 1.0 × 10-4 M 
D)  [OH-] = 0.5 M 
E)  pH = 1.2 
A)  pOH = 5.9 
B)  [H+] = 0.3 M 
C)  [H+] = 1.0 × 10-4 M 
D)  [OH-] = 0.5 M 
E)  pH = 1.2

Question 5

If you know Kb for ammonia, NH3, you can calculate the equilibrium constant Ka for the reaction
NH4+  NH3 + H+
by which of the following equations?

Accepted Answer

A)  Ka = KwKb 
B)  Ka = 1/Kb 
C)  Ka = Kb/Kw 
D)  Ka = Kw/Kb 
A)  Ka = KwKb 
B)  Ka = 1/Kb 
C)  Ka = Kb/Kw 
D)  Ka = Kw/Kb

Question 6

​Calculate [H+] in a 0.026 M solution of HCN, Ka = 6.2 ×10-10.

Accepted Answer

A)  6.5 ×​10-7 M 
B)  ​2.5 ×​10-9 M 
C)  ​6.2 ×​10-10 M 
D)  ​4.0 ×​10-6 M 
E)  ​1.5 ×​10-4 M 
A)  6.5 ×​10-7 M 
B)  ​2.5 ×​10-9 M 
C)  ​6.2 ×​10-10 M 
D)  ​4.0 ×​10-6 M 
E)  ​1.5 ×​10-4 M

Question 7

If solid sodium cyanide (NaCN) is dissolved in pure water, will the solution be acidic, neutral, or basic?

Accepted Answer

A)  acidic 
B)  neutral 
C)  basic 
A)  acidic 
B)  neutral 
C)  basic

Question 8

The following three equations represent equilibria that lie far to the right.
HNOS1U1B13S1U1B0(aq) + CNS1U1P1-S1S1P0(aq)   HCN(aq) + NOS1U1B13S1U1B0S1U1P1-S1S1P0(aq)
HCN(aq) + OHS1U1P1-S1S1P0(aq)   HS1U1B12S1U1B0O(l) + CNS1U1P1-S1S1P0(aq)
HS1U1B12S1U1B0O(l) + CHS1U1B13S1U1B0OS1U1P1-S1S1P0(aq)   CHS1U1B13S1U1B0OH(aq) + OHS1U1P1-S1S1P0(aq)
-Identify the strongest acid.

Accepted Answer

A)  HNO3 
B)  HCN 
C)  OH- 
D)  H2O 
E)  CH3OH 
A)  HNO3 
B)  HCN 
C)  OH- 
D)  H2O 
E)  CH3OH

Question 9

HOAc Ka = 1.8 ×10-5
H2CO3  Ka1 = 4.3 × 10-7, Ka2 = 5.6 × 10-11
Which of the following 0.01 M solutions has the highest pH?

Accepted Answer

A)  HOAc 
B)  NaHCO3 
C)  H2CO3 
D)  NaOAc 
E)  Na2CO3 
A)  HOAc 
B)  NaHCO3 
C)  H2CO3 
D)  NaOAc 
E)  Na2CO3

Question 10

Calculate the pOH of a 0.10 M solution of Ba(OH)2.

Accepted Answer

A)  13.30 
B)  0.70 
C)  13.00 
D)  1.00 
E)  none of these 
A)  13.30 
B)  0.70 
C)  13.00 
D)  1.00 
E)  none of these

Question 11

Which of the following aqueous solutions will have the highest pH?
For NH3, Kb = 1.8 × 10-5; for C2H3O2-, Kb = 5.6 × 10-10.

Accepted Answer

A)  2.0 M NH3 
B)  2.0 M HCl 
C)  2.0 M NaOH 
D)  2.0 M HC2H3O2 
E)  All these solutions will have the same pH. 
A)  2.0 M NH3 
B)  2.0 M HCl 
C)  2.0 M NaOH 
D)  2.0 M HC2H3O2 
E)  All these solutions will have the same pH.

Question 12

Which reaction does not proceed far to the right?

Accepted Answer

A)  HCN + OH- → H2O + CN- 
B)  HCl + H2O → H3O+ + Cl- 
C)    
D)  H3O+ + OH- → 2H2O 
E)    
A)  HCN + OH- → H2O + CN- 
B)  HCl + H2O → H3O+ + Cl- 
C)    
D)  H3O+ + OH- → 2H2O 
E)

Question 13

The pH of a 0.6 M solution of a weak acid is 4.0. What percent of the acid has ionized?

Accepted Answer

A)  0.02% 
B)  7% 
C)  4% 
D)  0.06% 
E)  2% 
A)  0.02% 
B)  7% 
C)  4% 
D)  0.06% 
E)  2%

Question 14

Which of the following statements is true for polyprotic acids?

Accepted Answer

A)  The values of Ka1 and Ka2 are dependent on the concentration of the acid. 
B)  Ka2     Ka1 
C)  Ka1     Ka2 
D)  pKa1     pKa2 
E)  C and D 
A)  The values of Ka1 and Ka2 are dependent on the concentration of the acid. 
B)  Ka2     Ka1 
C)  Ka1     Ka2 
D)  pKa1     pKa2 
E)  C and D

Question 15

Of the bases NaOH, H2O, CN-, SO42-, and HPO42-, which is the weakest? (Ka for HCN is 6.2 × 10-10; Ka for HSO4- is 1.2 × 10-2; and Ka3 for H3PO4, is 4.8 × 10-13)

Accepted Answer

A)  CN- 
B)  HPO42- 
C)  SO42- 
D)  NaOH 
E)  H2O 
A)  CN- 
B)  HPO42- 
C)  SO42- 
D)  NaOH 
E)  H2O

Question 16

Which of the following is the equilibrium constant expression for the dissociation of the weak acid HOCl?

Accepted Answer

A)    
B)  K = [H+][OCl-] 
C)    
D)    
E)  none of these 
A)    
B)  K = [H+][OCl-] 
C)    
D)    
E)  none of these

Question 17

Calculate the pH of a 0.21 M solution of NaA (Ka for HA is 2.1 × 10-4) at 25°C.

Accepted Answer

A)  11.82 
B)  5.50 
C)  8.50 
D)  3.00 
E)  2.18 
A)  11.82 
B)  5.50 
C)  8.50 
D)  3.00 
E)  2.18

Question 18

Consider two separate solutions of equal concentration. The first solution contains sodium hydroxide, and the second solution contains barium hydroxide. Which solution has the lower pH?

Accepted Answer

A)  The barium hydroxide solution. 
B)  The sodium hydroxide solution. 
C)  We need to know the concentrations to answer this question. 
D)  The pH's of the two solutions are equal. 
E)  We need to know the volumes to answer this question. 
A)  The barium hydroxide solution. 
B)  The sodium hydroxide solution. 
C)  We need to know the concentrations to answer this question. 
D)  The pH's of the two solutions are equal. 
E)  We need to know the volumes to answer this question.

Question 19

A monoprotic weak acid, when dissolved in water, is 0.92% dissociated and produces a solution with pH = 3.42. Calculate Ka for the acid.

Accepted Answer

A)  1.4 × 10-7 
B)  2.8 × 10-3 
C)  3.5 × 10-6 
D)  We need to know the initial concentration of the acid. 
E)  none of these 
A)  1.4 × 10-7 
B)  2.8 × 10-3 
C)  3.5 × 10-6 
D)  We need to know the initial concentration of the acid. 
E)  none of these

Question 20

The pH of a solution made of 0.100 mol of a weak monoprotic acid HA in 1.000 L of solution is 1.470. Calculate Ka for this acid.

Accepted Answer

A)  29.5 
B)  0 
C)  0.100 
D)  0.0174 
E)  0.0339 
A)  29.5 
B)  0 
C)  0.100 
D)  0.0174 
E)  0.0339

Calculate [H⁺] in a 1.2 × 10^-5 M solution of NH₄Cl. (K_b for NH₃ = 1.8 × 10^-5)

Calculate the pH of a 2.0 × 10^-5 M solution of HOC₆H₅. (K_a = 1.6 × 10^-10)

A 0.050 M aqueous solution of a weak monoprotic acid is 1.2% ionized at equilibrium at 25° C. Calculate K_a for this acid.

Which of the following indicates the most acidic solution?

If you know K_b for ammonia, NH₃, you can calculate the equilibrium constant K_a for the reaction NH₄⁺ NH₃ + H⁺by which of the following equations?

Calculate [H+] in a 0.026 M solution of HCN, K_a = 6.2 ×10^-10.

If solid sodium cyanide (NaCN) is dissolved in pure water, will the solution be acidic, neutral, or basic?

The following three equations represent equilibria that lie far to the right. HNO₃(aq) + CN^-(aq) HCN(aq) + NO₃^-(aq) HCN(aq) + OH^-(aq) H₂O(l) + CN^-(aq) H₂O(l) + CH₃O^-(aq) CH₃OH(aq) + OH^-(aq) -Identify the strongest acid.

HOAc K_a = 1.8 ×10^-5H₂CO₃ K_a1 = 4.3 × 10^-7,K_a2 = 5.6 × 10^-11 Which of the following 0.01 M solutions has the highest pH?

Calculate the pOH of a 0.10 M solution of Ba(OH)₂.

Which of the following aqueous solutions will have the highest pH? For NH₃, K_b = 1.8 × 10^-5; for C₂H₃O₂^-, K_b = 5.6 × 10^-10.

Which reaction does not proceed far to the right?

The pH of a 0.6 M solution of a weak acid is 4.0. What percent of the acid has ionized?

Which of the following statements is true for polyprotic acids?

Of the bases NaOH, H₂O, CN^-, SO₄^2-, and HPO₄^2-, which is the weakest? (K_a for HCN is 6.2 × 10^-10; K_a for HSO₄^- is 1.2 × 10^-2; and K_a3 for H₃PO₄, is 4.8 × 10^-13)

Which of the following is the equilibrium constant expression for the dissociation of the weak acid HOCl?

Calculate the pH of a 0.21 M solution of NaA (K_a for HA is 2.1 × 10^-4) at 25°C.

Consider two separate solutions of equal concentration. The first solution contains sodium hydroxide, and the second solution contains barium hydroxide. Which solution has the lower pH?

A monoprotic weak acid, when dissolved in water, is 0.92% dissociated and produces a solution with pH = 3.42. Calculate K_a for the acid.

The pH of a solution made of 0.100 mol of a weak monoprotic acid HA in 1.000 L of solution is 1.470. Calculate K_a for this acid.

Atoms, Molecules, and Ions

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Types of Chemical Reactions and Solution Stoichiometry

Gases

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Applications of Aqueous Equilibria

Energy, Enthalpy, and Thermochemistry

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Exam 7: Acids and Bases

Calculate [H+] in a 1.2 × 10-5 M solution of NH4Cl. (Kb for NH3 = 1.8 × 10-5)

Calculate the pH of a 2.0 × 10-5 M solution of HOC6H5. (Ka = 1.6 × 10-10)

A 0.050 M aqueous solution of a weak monoprotic acid is 1.2% ionized at equilibrium at 25° C. Calculate Ka for this acid.

Which of the following indicates the most acidic solution?

If you know Kb for ammonia, NH3, you can calculate the equilibrium constant Ka for the reaction NH4+ NH3 + H+ by which of the following equations?

​Calculate [H+] in a 0.026 M solution of HCN, Ka = 6.2 ×10-10.

If solid sodium cyanide (NaCN) is dissolved in pure water, will the solution be acidic, neutral, or basic?

The following three equations represent equilibria that lie far to the right. HNO3(aq) + CN-(aq) HCN(aq) + NO3-(aq) HCN(aq) + OH-(aq) H2O(l) + CN-(aq) H2O(l) + CH3O-(aq) CH3OH(aq) + OH-(aq) -Identify the strongest acid.

HOAc Ka = 1.8 ×10-5 H2CO3 Ka1 = 4.3 × 10-7, Ka2 = 5.6 × 10-11 Which of the following 0.01 M solutions has the highest pH?

Calculate the pOH of a 0.10 M solution of Ba(OH)2.

Which of the following aqueous solutions will have the highest pH? For NH3, Kb = 1.8 × 10-5; for C2H3O2-, Kb = 5.6 × 10-10.

Which reaction does not proceed far to the right?

The pH of a 0.6 M solution of a weak acid is 4.0. What percent of the acid has ionized?

Which of the following statements is true for polyprotic acids?

Of the bases NaOH, H2O, CN-, SO42-, and HPO42-, which is the weakest? (Ka for HCN is 6.2 × 10-10; Ka for HSO4- is 1.2 × 10-2; and Ka3 for H3PO4, is 4.8 × 10-13)

Which of the following is the equilibrium constant expression for the dissociation of the weak acid HOCl?

Calculate the pH of a 0.21 M solution of NaA (Ka for HA is 2.1 × 10-4) at 25°C.

Consider two separate solutions of equal concentration. The first solution contains sodium hydroxide, and the second solution contains barium hydroxide. Which solution has the lower pH?

A monoprotic weak acid, when dissolved in water, is 0.92% dissociated and produces a solution with pH = 3.42. Calculate Ka for the acid.

The pH of a solution made of 0.100 mol of a weak monoprotic acid HA in 1.000 L of solution is 1.470. Calculate Ka for this acid.

Atoms, Molecules, and Ions

Stoichiometry

Types of Chemical Reactions and Solution Stoichiometry

Gases

Chemical Equilibrium

Applications of Aqueous Equilibria

Energy, Enthalpy, and Thermochemistry

Spontaneity, Entropy, and Free Energy

Electrochemistry

Quantum Mechanics and Atomic Theory

Bonding: General Concepts

Covalent Bonding: Orbitals

Chemical Kinetics

Liquids and Solids

Properties of Solutions

The Representative Elements

Transition Metals and Coordination Chemistry

The Nucleus: a Chemists View

Organic and Biochemical Molecules

Filters

Calculate [H⁺] in a 1.2 × 10^-5 M solution of NH₄Cl. (K_b for NH₃ = 1.8 × 10^-5)

Calculate the pH of a 2.0 × 10^-5 M solution of HOC₆H₅. (K_a = 1.6 × 10^-10)

A 0.050 M aqueous solution of a weak monoprotic acid is 1.2% ionized at equilibrium at 25° C. Calculate K_a for this acid.

If you know K_b for ammonia, NH₃, you can calculate the equilibrium constant K_a for the reaction NH₄⁺ NH₃ + H⁺by which of the following equations?

Calculate [H+] in a 0.026 M solution of HCN, K_a = 6.2 ×10^-10.

The following three equations represent equilibria that lie far to the right. HNO₃(aq) + CN^-(aq) HCN(aq) + NO₃^-(aq) HCN(aq) + OH^-(aq) H₂O(l) + CN^-(aq) H₂O(l) + CH₃O^-(aq) CH₃OH(aq) + OH^-(aq) -Identify the strongest acid.

HOAc K_a = 1.8 ×10^-5H₂CO₃ K_a1 = 4.3 × 10^-7,K_a2 = 5.6 × 10^-11 Which of the following 0.01 M solutions has the highest pH?

Calculate the pOH of a 0.10 M solution of Ba(OH)₂.

Which of the following aqueous solutions will have the highest pH? For NH₃, K_b = 1.8 × 10^-5; for C₂H₃O₂^-, K_b = 5.6 × 10^-10.

Of the bases NaOH, H₂O, CN^-, SO₄^2-, and HPO₄^2-, which is the weakest? (K_a for HCN is 6.2 × 10^-10; K_a for HSO₄^- is 1.2 × 10^-2; and K_a3 for H₃PO₄, is 4.8 × 10^-13)

Calculate the pH of a 0.21 M solution of NaA (K_a for HA is 2.1 × 10^-4) at 25°C.

A monoprotic weak acid, when dissolved in water, is 0.92% dissociated and produces a solution with pH = 3.42. Calculate K_a for the acid.

The pH of a solution made of 0.100 mol of a weak monoprotic acid HA in 1.000 L of solution is 1.470. Calculate K_a for this acid.