Question 1

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 2

If the pH of a buffer solution is greater than the pKa value of the buffer acid,the buffer will have more capacity to neutralize added base than added acid.

Accepted Answer

A) True 
 B)False

Question 3

A change in pH will significantly affect the solubility of which,if any,of the following compounds?

Accepted Answer

A) BaF2 
B) CuCl 
C) CuBr 
D) AgI 
E) None of the solubilities will be significantly affected. 
A) BaF2 
B) CuCl 
C) CuBr 
D) AgI 
E) None of the solubilities will be significantly affected.

Question 4

Calculate the solubility of copper(II)carbonate,CuCO3,in 1.00 mol L-1 NH3.Ksp = 3.0 $\times$ 10-12 for CuCO3,Kf = 5.6 $\times$ 1011 for Cu(NH3)42+

Accepted Answer

0.16 mol L

Question 5

Calculate the solubility of silver chromate,Ag2CrO4,in 0.005 M Na2CrO4.Ksp = 2.6 $\times$ 10-12

Accepted Answer

A) 1.4 $\times$ 10-4 M 
B) 3.4 $\times$ 10-5 M 
C) 1.1 $\times$ 10-5 M 
D) 1.6 $\times$ 10-6 M 
E) -6 M 
A) 1.4 $\times$ 10-4 M 
B) 3.4 $\times$ 10-5 M 
C) 1.1 $\times$ 10-5 M 
D) 1.6 $\times$ 10-6 M 
E) -6 M

Question 6

A 25.0-mL sample of 1.00 M NH3 is titrated with 0.15 M HCl.What is the pH of the solution after 15.00 mL of acid have been added to the ammonia solution? Kb = 1.8 $\times$ 10-5

Accepted Answer

A) 10.26 
B) 9.30 
C) 9.21 
D) 8.30 
E) 8.21 
A) 10.26 
B) 9.30 
C) 9.21 
D) 8.30 
E) 8.21

Question 7

A 50.0-mL sample of 0.50 M HCl is titrated with 0.50 M NaOH.What is the pH of the solution after 28.0 mL of NaOH have been added to the acid?

Accepted Answer

A) 0.85 
B) 0.75 
C) 0.66 
D) 0.49 
E) 3.8 
A) 0.85 
B) 0.75 
C) 0.66 
D) 0.49 
E) 3.8

Question 8

Fe(NO3)3 (0.00100 mol)and KSCN (0.200 mol)are added to water to make exactly 1 liter of solution.The red complex ion FeSCN2+ is produced.Calculate the concentrations of Fe3+(aq)and FeSCN2+(aq)at equilibrium,if Kf of the FeSCN2+ is 8.9 $\times$ 102.

Accepted Answer

[Fe³⁺] = 5.6 @#LAT-DLM& 10

Question 9

Calculate the solubility of magnesium sulfate,MgSO4,when placed into a 0.10 M MgCl2 solution.
Ksp = 5.9 $\times$ 10-3

Accepted Answer

A) 4.2 $\times$ 10-2 M 
B) 5.9 $\times$ 10-2 M 
C) 7.7 $\times$ 10-2 M 
D) 3.5 $\times$ 10-5 M 
E) 3.5 $\times$ 10-6 M 
A) 4.2 $\times$ 10-2 M 
B) 5.9 $\times$ 10-2 M 
C) 7.7 $\times$ 10-2 M 
D) 3.5 $\times$ 10-5 M 
E) 3.5 $\times$ 10-6 M

Question 10

A buffer is to be prepared by adding solid sodium acetate to 0.10 M CH3COOH.Which of the following concentrations of sodium acetate will produce the most effective buffer?

Accepted Answer

A) 3.0 M CH3COONa 
B) 2.5 M CH3COONa 
C) 2.0 M CH3COONa 
D) 1.5 M CH3COONa 
E) 0.30 M CH3COONa 
A) 3.0 M CH3COONa 
B) 2.5 M CH3COONa 
C) 2.0 M CH3COONa 
D) 1.5 M CH3COONa 
E) 0.30 M CH3COONa

Question 11

When a strong acid is titrated with a weak 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 the pKb 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 the pKb of the base.

Question 12

A buffer is prepared by adding 0.5 mol of solid sodium hydroxide to 1.0 L of 1.0 M acetic acid (CH3COOH).What is the pH of the buffer?

Accepted Answer

A) The pH will be pKa - 0.30,where pKa is that of acetic acid. 
B) The pH will be greater than the pKa for acetic acid. 
C) The pH will be less than the value in answer a. 
D) The pH will be equal to the pKa for acetic acid. 
E) More information is needed to solve the problem. 
A) The pH will be pKa - 0.30,where pKa is that of acetic acid. 
B) The pH will be greater than the pKa for acetic acid. 
C) The pH will be less than the value in answer a. 
D) The pH will be equal to the pKa for acetic acid. 
E) More information is needed to solve the problem.

Question 13

A solution is prepared by adding 100 mL of 0.2 M hydrochloric acid to 100 mL of 0.4 M sodium formate.Is this a buffer solution,and if so,what is its pH?

Accepted Answer

A) It is a buffer,pH > pKa of formic acid. 
B) It is a buffer,pH a of formic acid. 
C) It is a buffer,pH = pKa of formic acid. 
D) It is a buffer,pH = pKb of sodium formate. 
E) Since hydrochloric acid is a strong acid,this is not a buffer. 
A) It is a buffer,pH > pKa of formic acid. 
B) It is a buffer,pH a of formic acid. 
C) It is a buffer,pH = pKa of formic acid. 
D) It is a buffer,pH = pKb of sodium formate. 
E) Since hydrochloric acid is a strong acid,this is not a buffer.

Question 14

The indicator propyl red has Ka = 3.3 $\times$ 10-6.What would be the approximate pH range over which it would change color?

Accepted Answer

A) 3.5-5.5 
B) 4.5-6.5 
C) 5.5-7.5 
D) 6.5-8.5 
E) None of these choices is correct. 
A) 3.5-5.5 
B) 4.5-6.5 
C) 5.5-7.5 
D) 6.5-8.5 
E) None of these choices is correct.

Question 15

Citric acid has an acid dissociation constant of 8.4 $\times$ 10-4.It would be most effective for preparation of a buffer with a pH of

Accepted Answer

A) 2 
B) 3 
C) 4 
D) 5 
E) 6 
A) 2 
B) 3 
C) 4 
D) 5 
E) 6

Question 16

An acetic acid buffer containing 0.50 M CH3COOH and 0.50 M CH3COONa has a pH of 4.74.What will the pH be after 0.0020 mol of HCl has been added to 100.0 mL of the buffer?

Accepted Answer

A) 4.77 
B) 4.71 
C) 4.68 
D) 4.62 
E) None of these choices is correct. 
A) 4.77 
B) 4.71 
C) 4.68 
D) 4.62 
E) None of these choices is correct.

Question 17

A 10.0-mL sample of 0.75 M CH3CH2COOH is titrated with 0.30 M NaOH.What is the pH of the solution after 22.0 mL of NaOH have been added to the acid?
Ka = 1.3 $\times$ 10-5

Accepted Answer

A) 5.75 
B) 4.94 
C) 4.83 
D) 4.02 
E) 3.95 
A) 5.75 
B) 4.94 
C) 4.83 
D) 4.02 
E) 3.95

Question 18

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 will be a buffer solution. 
A) CH3COOH,NaH2PO4 
B) H2CO3,HCO3- 
C) H2PO4-,HCO3- 
D) HSO4-,HSO3- 
E) None of these will be a buffer solution.

Question 19

A 20.0-mL sample of 0.25 M HNO3 is titrated with 0.15 M Na OH.What is the pH of the solution after 30.0 mL of NaOH have been added to the acid?

Accepted Answer

A) 2.00 
B) 1.60 
C) 1.05 
D) 1.00 
E) None of these choices is correct. 
A) 2.00 
B) 1.60 
C) 1.05 
D) 1.00 
E) None of these choices is correct.

Question 20

The solubility of calcium chromate is 1.56 $\times$ 10-3 g/100 mL of solution.What is the Ksp for CaCrO4?

Accepted Answer

A) 2.4 $\times$ 10-4 
B) 1.5 $\times$ 10-5 
C) 7.6 $\times$ 10-6 
D) 1.0 $\times$ 10-8 
E) -8 
A) 2.4 $\times$ 10-4 
B) 1.5 $\times$ 10-5 
C) 7.6 $\times$ 10-6 
D) 1.0 $\times$ 10-8 
E) -8

Exam 19: Ionic Equilibria in Aqueous Systems

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?

If the pH of a buffer solution is greater than the pKa value of the buffer acid,the buffer will have more capacity to neutralize added base than added acid.

A change in pH will significantly affect the solubility of which,if any,of the following compounds?

Calculate the solubility of copper(II)carbonate,CuCO3,in 1.00 mol L-1 NH3.Ksp = 3.0 ×\times× 10-12 for CuCO3,Kf = 5.6 ×\times× 1011 for Cu(NH3)42+

Calculate the solubility of silver chromate,Ag2CrO4,in 0.005 M Na2CrO4.Ksp = 2.6 ×\times× 10-12

A 25.0-mL sample of 1.00 M NH3 is titrated with 0.15 M HCl.What is the pH of the solution after 15.00 mL of acid have been added to the ammonia solution? Kb = 1.8 ×\times× 10-5

A 50.0-mL sample of 0.50 M HCl is titrated with 0.50 M NaOH.What is the pH of the solution after 28.0 mL of NaOH have been added to the acid?

Fe(NO3)3 (0.00100 mol)and KSCN (0.200 mol)are added to water to make exactly 1 liter of solution.The red complex ion FeSCN2+ is produced.Calculate the concentrations of Fe3+(aq)and FeSCN2+(aq)at equilibrium,if Kf of the FeSCN2+ is 8.9 ×\times× 102.

Calculate the solubility of magnesium sulfate,MgSO4,when placed into a 0.10 M MgCl2 solution. Ksp = 5.9 ×\times× 10-3

A buffer is to be prepared by adding solid sodium acetate to 0.10 M CH3COOH.Which of the following concentrations of sodium acetate will produce the most effective buffer?

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

A buffer is prepared by adding 0.5 mol of solid sodium hydroxide to 1.0 L of 1.0 M acetic acid (CH3COOH).What is the pH of the buffer?

A solution is prepared by adding 100 mL of 0.2 M hydrochloric acid to 100 mL of 0.4 M sodium formate.Is this a buffer solution,and if so,what is its pH?

The indicator propyl red has Ka = 3.3 ×\times× 10-6.What would be the approximate pH range over which it would change color?

Citric acid has an acid dissociation constant of 8.4 ×\times× 10-4.It would be most effective for preparation of a buffer with a pH of

An acetic acid buffer containing 0.50 M CH3COOH and 0.50 M CH3COONa has a pH of 4.74.What will the pH be after 0.0020 mol of HCl has been added to 100.0 mL of the buffer?

A 10.0-mL sample of 0.75 M CH3CH2COOH is titrated with 0.30 M NaOH.What is the pH of the solution after 22.0 mL of NaOH have been added to the acid? Ka = 1.3 ×\times× 10-5

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

A 20.0-mL sample of 0.25 M HNO3 is titrated with 0.15 M Na OH.What is the pH of the solution after 30.0 mL of NaOH have been added to the acid?

The solubility of calcium chromate is 1.56 ×\times× 10-3 g/100 mL of solution.What is the Ksp for CaCrO4?

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 Solutions

The Main-Group Elements: Applying Principles of Bonding and Structure

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 Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

If the pH of a buffer solution is greater than the pK_a value of the buffer acid,the buffer will have more capacity to neutralize added base than added acid.

Calculate the solubility of copper(II)carbonate,CuCO₃,in 1.00 mol L^-1 NH₃.K_sp = 3.0 $\times$ 10^-12 for CuCO₃,K_f = 5.6 $\times$ 10¹¹ for Cu(NH₃)₄²⁺

Calculate the solubility of silver chromate,Ag₂CrO₄,in 0.005 M Na₂CrO₄.K_sp = 2.6 $\times$ 10^-12

A 25.0-mL sample of 1.00 M NH₃ is titrated with 0.15 M HCl.What is the pH of the solution after 15.00 mL of acid have been added to the ammonia solution? K_b = 1.8 $\times$ 10^-5

Fe(NO₃)₃ (0.00100 mol)and KSCN (0.200 mol)are added to water to make exactly 1 liter of solution.The red complex ion FeSCN²⁺ is produced.Calculate the concentrations of Fe³⁺(aq)and FeSCN²⁺(aq)at equilibrium,if K_f of the FeSCN²⁺ is 8.9 $\times$ 10².

Calculate the solubility of magnesium sulfate,MgSO₄,when placed into a 0.10 M MgCl₂ solution. K_sp = 5.9 $\times$ 10^-3

A buffer is to be prepared by adding solid sodium acetate to 0.10 M CH₃COOH.Which of the following concentrations of sodium acetate will produce the most effective buffer?

A buffer is prepared by adding 0.5 mol of solid sodium hydroxide to 1.0 L of 1.0 M acetic acid (CH₃COOH).What is the pH of the buffer?

The indicator propyl red has K_a = 3.3 $\times$ 10^-6.What would be the approximate pH range over which it would change color?

Citric acid has an acid dissociation constant of 8.4 $\times$ 10^-4.It would be most effective for preparation of a buffer with a pH of

An acetic acid buffer containing 0.50 M CH₃COOH and 0.50 M CH₃COONa has a pH of 4.74.What will the pH be after 0.0020 mol of HCl has been added to 100.0 mL of the buffer?

A 10.0-mL sample of 0.75 M CH₃CH₂COOH is titrated with 0.30 M NaOH.What is the pH of the solution after 22.0 mL of NaOH have been added to the acid? K_a = 1.3 $\times$ 10^-5

A 20.0-mL sample of 0.25 M HNO₃ is titrated with 0.15 M Na OH.What is the pH of the solution after 30.0 mL of NaOH have been added to the acid?

The solubility of calcium chromate is 1.56 $\times$ 10^-3 g/100 mL of solution.What is the K_sp for CaCrO₄?