Question 1

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.F) A) and E)
G) A) and B)

Question 2

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.F) A) and E)
G) A) and C)

Question 3

A CH3COOH/CH3COO¯ buffer can be produced by adding a strong acid to a solution of CH3COO¯ ions.

Accepted Answer

A) True 
 B)False

Question 4

When a weak 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 determined by the sizes of Ka and Kb.
E)   is no longer affected by addition of base.F) A) and E)
G) A) and D)

Question 5

A 20.0-mL sample of 0.25 M HNO3 is titrated with 0.15 M NaOH. 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.F) C) and D)
G) A) and B)

Question 6

A saturated solution of calcium hydroxide, Ca(OH) 2, is in contact with excess solid Ca(OH) 2. Which of the following statements correctly describes what will happen when aqueous HCl (a strong acid)  is added to this mixture, and system returns to equilibrium? (For Ca(OH) 2, Ksp = 6.5 * 10¯6)

Accepted Answer

A)   The solubility of Ca(OH) 2 will be unchanged.
B)   The OH¯ concentration will decrease and the Ca2+ concentration will increase.
C)   The OH¯ concentration will increase and the Ca2+ concentration will decrease.
D)   The concentrations of both Ca2+ and OH¯ will increase.
E)   The solubility of Ca(OH) 2 will decrease.F) B) and C)
G) None of the above

Question 7

A buffer is prepared by adding 150 mL of 1.0 M NaOH to 250 mL of 1.0 M NaH2PO4. How many moles of HCl must be added to this buffer solution to change the pH by 0.18 units? If necessary, assume the total volume remains unchanged at 400 mL.

Accepted Answer

A)   0.025 mol HCl
B)   0.063 mol HCl
C)   0.082 mol HCl
D)   0.50 mol HCl
E)   1.0 mol HClF) B) and E)
G) A) and D)

Question 8

A lab technician adds 0.015 mol of KOH to 1.00 L of 0.0010 M Ca(NO3) 2. Ksp = 6.5 *10¯6 for Ca(OH) 2. Which of the following statements is correct?

Accepted Answer

A)   Calcium hydroxide precipitates until the solution is saturated.
B)   The solution is unsaturated and no precipitate forms.
C)   The concentration of calcium ions is reduced by the addition of the hydroxide ions.
D)   One must know Ksp for calcium nitrate to make meaningful predictions on this system.
E)   The presence of KOH will raise the solubility of Ca(NO3) 2.F) All of the above
G) C) and E)

Question 9

The solubility of salt MX (solubility product constant Ksp) in water will always be greater than that of salt MX3 (solubility product constant K'sp) provided that Ksp > K'sp.

Accepted Answer

A) True 
 B)False

Question 10

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

Accepted Answer

A)   3.5 to 5.5
B)   4.5 to 6.5
C)   5.5 to 7.5
D)   6.5 to 8.5
E)   None of these choices is correct.F) A) and E)
G) B) and E)

Question 11

Consider the dissolution of MnS in water (Ksp = 3.0 * 10¯14) . sp = 3.0 * 10¯14) .   How is the solubility of manganese(II)  sulfide affected by the addition of aqueous potassium hydroxide to the system? A)  The solubility will be unchanged. B)  The solubility will decrease. C)  The solubility will increase. D)  The amount of KOH added must be known before its effect can be predicted. E)  The pKa of H2S is needed before a reliable prediction can be made." class="answers-bank-image d-inline" rel="preload" > How is the solubility of manganese(II)  sulfide affected by the addition of aqueous potassium hydroxide to the system?

Accepted Answer

A)   The solubility will be unchanged.
B)   The solubility will decrease.
C)   The solubility will increase.
D)   The amount of KOH added must be known before its effect can be predicted.
E)   The pKa of H2S is needed before a reliable prediction can be made.F) D) and E)
G) B) and E)

Question 12

Buffer solutions with the component concentrations shown below were prepared. Which of them should have the highest pH?

Accepted Answer

A)   [H2PO4¯] = 0.50 M, [HPO42¯] = 0.50 M
B)   [H2PO4¯] = 1.0 M, [HPO42¯] = 1.0 M
C)   [H2PO4¯] = 1.0 M, [HPO42¯] = 0.50 M
D)   [H2PO4¯] = 0.50 M, [HPO42¯] = 1.0 M
E)   [H2PO4¯] = 0.75 M, [HPO42¯] = 1.0 MF) D) and E)
G) A) and E)

Question 13

What is the maximum mass of KCl that can be added to 1.0 L of a 0.010 M lead(II)  chloride solution without causing any precipitation of lead(II)  chloride? Assume that addition of KCl does not affect the solution volume. For lead(II)  chloride, Ksp = 1.6 * 10¯5

Accepted Answer

A)   3.0 g
B)   1.5 g
C)   0.8 g
D)   0.8 g.
E)   0.2 gF) B) and D)
G) A) and B)

Question 14

A 20.0-mL sample of 0.50 M H2C6H6O6 (ascorbic acid, a diprotic acid)  was titrated with 0.50 M NaOH. The following data were gathered during the titration. 2C6H6O6 (ascorbic acid, a diprotic acid)  was titrated with 0.50 M NaOH. The following data were gathered during the titration.   What is Ka2 for ascorbic acid? A)  6.8 *10¯5 B)  6.2 * 10¯6 C)  6.2 * 10¯7 D)  6.2 * 10¯8 E)  2.8 * 10¯12" class="answers-bank-image d-inline" rel="preload" > What is Ka2 for ascorbic acid?

Accepted Answer

A)   6.8 *10¯5
B)   6.2 * 10¯6
C)   6.2 * 10¯7
D)   6.2 * 10¯8
E)   2.8 * 10¯12F) A) and E)
G) A) and D)

Question 15

Which one of the following aqueous solutions, when mixed with an equal volume of 0.10 mol L¯1 aqueous NH3, will produce a buffer solution?

Accepted Answer

A)   0.10 mol L¯1 HCl
B)   0.20 mol L¯1 HCl
C)   0.10 mol L¯1 CH3COOH
D)   0.050 mol L¯1 NaOH
E)   0.20 mol L¯1 NH4ClF) A) and E)
G) B) and C)

Question 16

The salts X(NO3) 2 and Y(NO3) 2 (where X+ and Y+ are metal ions)  are dissolved in water to give a solution which is 0.1 M in each of them. Which of the answers gives the concentration of chloride ions will precipitate the most YCl2 without precipitating any XCl2? Given Ksp values: XCl2, 2 * 10¯5; YCl2, 1 *10¯10

Accepted Answer

A)   1 M Cl¯
B)   0.1 M Cl¯
C)   0.01 M Cl¯
D)   0.001 M Cl¯
E)   0.0001 M Cl¯F) A) and E)
G) B) and D)

Question 17

Calculate the solubility of lead(II)  iodide, PbI2, in 0.025 M KI. Ksp = 7.9 *10¯9

Accepted Answer

A)   4.5 *10¯2 M
B)   2.8 * 10¯2 M
C)   8.9 * 10¯5 M
D)   5.0 * 10¯5 M
E)   1.3 * 10¯5 MF) All of the above
G) A) and E)

Question 18

A diprotic acid H2A has Ka1 = 1 *10¯4 and Ka2 = 1 * 10¯8. The corresponding base A2¯ is titrated with aqueous HCl, both solutions being 0.1 mol L¯1. Which one of the following diagrams best represents the titration curve which will be seen?

Accepted Answer

A)   2A has Ka1 = 1 *10¯4 and Ka2 = 1 * 10¯8. The corresponding base A2¯ is titrated with aqueous HCl, both solutions being 0.1 mol L¯1. Which one of the following diagrams best represents the titration curve which will be seen? 
A)     
B)     
C)     
D)     
E)    " class="answers-bank-image d-inline" rel="preload" >
B)   2A has Ka1 = 1 *10¯4 and Ka2 = 1 * 10¯8. The corresponding base A2¯ is titrated with aqueous HCl, both solutions being 0.1 mol L¯1. Which one of the following diagrams best represents the titration curve which will be seen? 
A)     
B)     
C)     
D)     
E)    " class="answers-bank-image d-inline" rel="preload" >
C)   2A has Ka1 = 1 *10¯4 and Ka2 = 1 * 10¯8. The corresponding base A2¯ is titrated with aqueous HCl, both solutions being 0.1 mol L¯1. Which one of the following diagrams best represents the titration curve which will be seen? 
A)     
B)     
C)     
D)     
E)    " class="answers-bank-image d-inline" rel="preload" >
D)   2A has Ka1 = 1 *10¯4 and Ka2 = 1 * 10¯8. The corresponding base A2¯ is titrated with aqueous HCl, both solutions being 0.1 mol L¯1. Which one of the following diagrams best represents the titration curve which will be seen? 
A)     
B)     
C)     
D)     
E)    " class="answers-bank-image d-inline" rel="preload" >
E)   2A has Ka1 = 1 *10¯4 and Ka2 = 1 * 10¯8. The corresponding base A2¯ is titrated with aqueous HCl, both solutions being 0.1 mol L¯1. Which one of the following diagrams best represents the titration curve which will be seen? 
A)     
B)     
C)     
D)     
E)    " class="answers-bank-image d-inline" rel="preload" >F) A) and B)
G) All of the above

Question 19

The lab technician Anna Lytic adds 2.20 mol KOH to 1.00 L of 0.5 M Al(NO3) 3. What is the concentration of aluminum ions after the aluminum nitrate has reacted with the potassium hydroxide? Kf = 3.0 * 1033 for Al(OH) 4¯

Accepted Answer

A)   1.8 * 10¯7 M
B)   9.l * 10¯18 M
C)   1.0 * 10¯31 M
D)   3.3 * 10¯34 M
E)   7.l *10¯36 MF) A) and D)
G) C) and D)

Question 20

A buffer is prepared by adding 1.00 L of 1.0 M HCl to 750 mL of 1.5 M NaHCOO. What is the pH of this buffer? Ka = 1.7 * 10¯4

Accepted Answer

A)   2.87
B)   3.72
C)   3.82
D)   3.95
E)   4.66F) A) and D)
G) A) and E)

Exam 19: Ionic Equilibria in Aqueous Systems

The indicator propyl red has K_a = 3.3 * 10¯⁶. What would be the approximate pH range over which it would change color?

Correct Answer
verified

Calculate the solubility of lead(II) iodide, PbI₂, in 0.025 M KI. K_sp = 7.9 *10¯⁹

Correct Answer
verified

A CH₃COOH/CH₃COO¯ buffer can be produced by adding a strong acid to a solution of CH₃COO¯ ions.

Correct Answer
verified

A diprotic acid H₂A has K_a1 = 1 10¯⁴ and K_a2 = 1 10¯⁸. The corresponding base A²¯ is titrated with aqueous HCl, both solutions being 0.1 mol L¯¹. Which one of the following diagrams best represents the titration curve which will be seen?

Correct Answer
verified

The lab technician Anna Lytic adds 2.20 mol KOH to 1.00 L of 0.5 M Al(NO₃) ₃. What is the concentration of aluminum ions after the aluminum nitrate has reacted with the potassium hydroxide? K_f = 3.0 * 10³³ for Al(OH) ₄¯

Correct Answer
verified

A buffer is prepared by adding 150 mL of 1.0 M NaOH to 250 mL of 1.0 M NaH₂PO₄. How many moles of HCl must be added to this buffer solution to change the pH by 0.18 units? If necessary, assume the total volume remains unchanged at 400 mL.

Correct Answer
verified

The solubility of salt MX (solubility product constant K_sp) in water will always be greater than that of salt MX₃ (solubility product constant K'_sp) provided that K_sp > K'_sp.

Correct Answer
verified

Buffer solutions with the component concentrations shown below were prepared. Which of them should have the highest pH?

Correct Answer
verified

Correct Answer
verified

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?

Correct Answer
verified

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

Correct Answer
verified

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

Correct Answer
verified

What is the maximum mass of KCl that can be added to 1.0 L of a 0.010 M lead(II) chloride solution without causing any precipitation of lead(II) chloride? Assume that addition of KCl does not affect the solution volume. For lead(II) chloride, K_sp = 1.6 * 10¯⁵

Correct Answer
verified

Consider the dissolution of MnS in water (K_sp = 3.0 * 10¯¹⁴) . How is the solubility of manganese(II) sulfide affected by the addition of aqueous potassium hydroxide to the system?

Correct Answer
verified

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?

Correct Answer
verified

A lab technician adds 0.015 mol of KOH to 1.00 L of 0.0010 M Ca(NO₃) ₂. K_sp = 6.5 *10¯⁶ for Ca(OH) ₂. Which of the following statements is correct?

Correct Answer
verified

Which one of the following aqueous solutions, when mixed with an equal volume of 0.10 mol L¯¹ aqueous NH₃, will produce a buffer solution?

Correct Answer
verified

Correct Answer
verified

A 20.0-mL sample of 0.50 M H₂C₆H₆O₆ (ascorbic acid, a diprotic acid) was titrated with 0.50 M NaOH. The following data were gathered during the titration. What is K_a2 for ascorbic acid?

Correct Answer
verified

A buffer is prepared by adding 1.00 L of 1.0 M HCl to 750 mL of 1.5 M NaHCOO. What is the pH of this buffer? K_a = 1.7 * 10¯⁴

Correct Answer
verified

Exam 19: Ionic Equilibria in Aqueous Systems

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

Correct AnswerverifiedShow Answer

Calculate the solubility of lead(II) iodide, PbI2, in 0.025 M KI. Ksp = 7.9 *10¯9

Correct AnswerverifiedShow Answer

A CH3COOH/CH3COO¯ buffer can be produced by adding a strong acid to a solution of CH3COO¯ ions.

Correct AnswerverifiedShow Answer

A diprotic acid H2A has Ka1 = 1 *10¯4 and Ka2 = 1 * 10¯8. The corresponding base A2¯ is titrated with aqueous HCl, both solutions being 0.1 mol L¯1. Which one of the following diagrams best represents the titration curve which will be seen?

Correct AnswerverifiedShow Answer

The lab technician Anna Lytic adds 2.20 mol KOH to 1.00 L of 0.5 M Al(NO3) 3. What is the concentration of aluminum ions after the aluminum nitrate has reacted with the potassium hydroxide? Kf = 3.0 * 1033 for Al(OH) 4¯

Correct AnswerverifiedShow Answer

A buffer is prepared by adding 150 mL of 1.0 M NaOH to 250 mL of 1.0 M NaH2PO4. How many moles of HCl must be added to this buffer solution to change the pH by 0.18 units? If necessary, assume the total volume remains unchanged at 400 mL.

Correct AnswerverifiedShow Answer

The solubility of salt MX (solubility product constant Ksp) in water will always be greater than that of salt MX3 (solubility product constant K'sp) provided that Ksp > K'sp.

Correct AnswerverifiedShow Answer

Buffer solutions with the component concentrations shown below were prepared. Which of them should have the highest pH?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

What is the maximum mass of KCl that can be added to 1.0 L of a 0.010 M lead(II) chloride solution without causing any precipitation of lead(II) chloride? Assume that addition of KCl does not affect the solution volume. For lead(II) chloride, Ksp = 1.6 * 10¯5

Correct AnswerverifiedShow Answer

Consider the dissolution of MnS in water (Ksp = 3.0 * 10¯14) . How is the solubility of manganese(II) sulfide affected by the addition of aqueous potassium hydroxide to the system?

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

A lab technician adds 0.015 mol of KOH to 1.00 L of 0.0010 M Ca(NO3) 2. Ksp = 6.5 *10¯6 for Ca(OH) 2. Which of the following statements is correct?

Correct AnswerverifiedShow Answer

Which one of the following aqueous solutions, when mixed with an equal volume of 0.10 mol L¯1 aqueous NH3, will produce a buffer solution?

Correct AnswerverifiedShow Answer

A saturated solution of calcium hydroxide, Ca(OH) 2, is in contact with excess solid Ca(OH) 2. Which of the following statements correctly describes what will happen when aqueous HCl (a strong acid) is added to this mixture, and system returns to equilibrium? (For Ca(OH) 2, Ksp = 6.5 * 10¯6)

Correct AnswerverifiedShow Answer

A 20.0-mL sample of 0.50 M H2C6H6O6 (ascorbic acid, a diprotic acid) was titrated with 0.50 M NaOH. The following data were gathered during the titration. What is Ka2 for ascorbic acid?

Correct AnswerverifiedShow Answer

A buffer is prepared by adding 1.00 L of 1.0 M HCl to 750 mL of 1.5 M NaHCOO. What is the pH of this buffer? Ka = 1.7 * 10¯4

Correct AnswerverifiedShow Answer

The indicator propyl red has K_a = 3.3 * 10¯⁶. What would be the approximate pH range over which it would change color?

Correct Answer
verified

Calculate the solubility of lead(II) iodide, PbI₂, in 0.025 M KI. K_sp = 7.9 *10¯⁹

Correct Answer
verified

A CH₃COOH/CH₃COO¯ buffer can be produced by adding a strong acid to a solution of CH₃COO¯ ions.

Correct Answer
verified

A diprotic acid H₂A has K_a1 = 1 10¯⁴ and K_a2 = 1 10¯⁸. The corresponding base A²¯ is titrated with aqueous HCl, both solutions being 0.1 mol L¯¹. Which one of the following diagrams best represents the titration curve which will be seen?

Correct Answer
verified

The lab technician Anna Lytic adds 2.20 mol KOH to 1.00 L of 0.5 M Al(NO₃) ₃. What is the concentration of aluminum ions after the aluminum nitrate has reacted with the potassium hydroxide? K_f = 3.0 * 10³³ for Al(OH) ₄¯

Correct Answer
verified

A buffer is prepared by adding 150 mL of 1.0 M NaOH to 250 mL of 1.0 M NaH₂PO₄. How many moles of HCl must be added to this buffer solution to change the pH by 0.18 units? If necessary, assume the total volume remains unchanged at 400 mL.

Correct Answer
verified

The solubility of salt MX (solubility product constant K_sp) in water will always be greater than that of salt MX₃ (solubility product constant K'_sp) provided that K_sp > K'_sp.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

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

Correct Answer
verified

Correct Answer
verified

What is the maximum mass of KCl that can be added to 1.0 L of a 0.010 M lead(II) chloride solution without causing any precipitation of lead(II) chloride? Assume that addition of KCl does not affect the solution volume. For lead(II) chloride, K_sp = 1.6 * 10¯⁵

Correct Answer
verified

Consider the dissolution of MnS in water (K_sp = 3.0 * 10¯¹⁴) . How is the solubility of manganese(II) sulfide affected by the addition of aqueous potassium hydroxide to the system?

Correct Answer
verified

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?

Correct Answer
verified

A lab technician adds 0.015 mol of KOH to 1.00 L of 0.0010 M Ca(NO₃) ₂. K_sp = 6.5 *10¯⁶ for Ca(OH) ₂. Which of the following statements is correct?

Correct Answer
verified

Which one of the following aqueous solutions, when mixed with an equal volume of 0.10 mol L¯¹ aqueous NH₃, will produce a buffer solution?

Correct Answer
verified

Correct Answer
verified

A 20.0-mL sample of 0.50 M H₂C₆H₆O₆ (ascorbic acid, a diprotic acid) was titrated with 0.50 M NaOH. The following data were gathered during the titration. What is K_a2 for ascorbic acid?

Correct Answer
verified

A buffer is prepared by adding 1.00 L of 1.0 M HCl to 750 mL of 1.5 M NaHCOO. What is the pH of this buffer? K_a = 1.7 * 10¯⁴

Correct Answer
verified