Question 1

A solution is prepared by dissolving 20.0 g of K2HPO4 and 25.0 g of KH2PO4 in enough water to produce 1.0 L of solution. What is the pH of this buffer? For phosphoric acid (H3PO4) , Ka2 = 6.2 × 10-8.

Accepted Answer

A)   7.70
B)   7.42
C)   7.21
D)   7.00
E)   6.72F) A) and E)
G) A) and B)

Question 2

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 B)
G) B) and D)

Question 3

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

Accepted Answer

A)   1.4 × 10-4 M
B)   3.4 × 10-5 M
C)   1.1 × 10-5 M
D)   1.6 × 10-6 M
E)   -6 MF) A) and B)
G) A) and D)

Question 4

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 × 10-4
C)   CH3COOH, Ka = 1.8 × 10-5
D)   C5H5O5COOH, Ka = 4.0 × 10-6
E)   HBrO, Ka = 2.3 × 10-9F) B) and E)
G) D) and E)

Question 5

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 the aboveF) B) and D)
G) B) and C)

Question 6

If 10.0 g of NaF and 20.0 g of HF are dissolved in water to make one liter of solution, what will the pH be? For HF, Ka = 6.8 × 10-4.

Accepted Answer

A)   7.13
B)   2.54
C)   1.57
D)   3.17
E)   4.86F) None of the above
G) A) and E)

Question 7

What is the pH of a buffer that consists of 0.45 M CH3COOH and 0.35 M CH3COONa? Ka = 1.8 × 10-5

Accepted Answer

A)   4.49
B)   4.64
C)   4.85
D)   5.00
E)   5.52F) A) and B)
G) A) and C)

Question 8

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. Using the Ksp values listed below, decide which aqueous reagent, if any, will definitely precipitate X+ before precipitating Y+ from solution. Given Ksp values:
XCl2, 1 × 10-5 YCl2, 1 × 10-10 X(OH) 2, 1 × 10-10 Y(OH) 2, 1 × 10-5

Accepted Answer

A)   1 M NH3
B)   1 M HCl
C)   1 M HNO3
D)   1 M NaCl
E)   None of the above reagents will accomplish the precipitation.F) All of the above
G) B) and E)

Question 9

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) A) and B)
G) A) and C)

Question 10

The solubility of silver chromate is 0.0287 g/1.0 L of solution. What is the Ksp for Ag2CrO4?

Accepted Answer

A)   9.5 × 10-5
B)   2.4 × 10-5
C)   2.6 × 10-12
D)   6.5 × 10-13
E)   -13F) B) and E)
G) None of the above

Question 11

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) B) and D)
G) B) and C)

Question 12

What is the pH of a buffer that consists of 0.20 M NaH2PO4 and 0.40 M Na2HPO4? For NaH2PO4, Ka = 6.2 × 10-8

Accepted Answer

A)   6.51
B)   6.91
C)   7.51
D)   7.90
E)   8.13F) B) and D)
G) B) and C)

Question 13

Which one of the following is the best representation of the titration curve which will be obtained in the titration of a weak acid (0.10 mol L-1)  with a strong base of the same concentration?

Accepted Answer

A)   -1)  with a strong base of the same concentration? 
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D) undefined

Question 14

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) All of the above
G) C) and D)

Question 15

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) All of the above
G) A) and D)

Question 16

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)   3.8F) A) and E)
G) C) and E)

Question 17

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. Using the Ksp values listed below, decide which aqueous reagent, if any, will definitely precipitate X+ before precipitating Y+ from solution. Given Ksp values:
XCl2, 1 × 10-5 YCl2, 1 × 10-10 X(OH) 2, 1 × 10-10  Y(OH) 2, 1 × 10-5

Accepted Answer

A)   1 M NaNO3
B)   1 M HCl
C)   1 M HNO3
D)   1 M NaCl
E)   None of the above reagents will accomplish the precipitation.F) A) and E)
G) A) and D)

Question 18

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 19

Silver phosphate, Ag3PO4, is an ionic compound with a solubility product constant Ksp of 2.6 × 10-18. Calculate the solubility of this compound in
a. pure water.
b. 0.20 mol L-1 Na3PO4 solution.

Accepted Answer

a. 1.8 × 1...

Question 20

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 the aboveF) A) and D)
G) A) and E)

Exam 19: Ionic Equilibria in Aqueous Systems

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
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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.

Correct Answer
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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

Correct Answer
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A solution is prepared by dissolving 20.0 g of K₂HPO₄ and 25.0 g of KH₂PO₄ in enough water to produce 1.0 L of solution. What is the pH of this buffer? For phosphoric acid (H₃PO₄) , K_a2 = 6.2 × 10^-8.

Correct Answer
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Correct Answer
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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
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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
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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?

Correct Answer
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Silver phosphate, Ag₃PO₄, is an ionic compound with a solubility product constant K_sp of 2.6 × 10^-18. Calculate the solubility of this compound in a. pure water. b. 0.20 mol L^-1 Na₃PO₄ solution.

Correct Answer
verified
a. 1.8 × 1...
View Answer

Correct Answer
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What is the pH of a buffer that consists of 0.45 M CH₃COOH and 0.35 M CH₃COONa? K_a = 1.8 × 10^-5

Correct Answer
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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
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Which one of the following is the best representation of the titration curve which will be obtained in the titration of a weak acid (0.10 mol L^-1) with a strong base of the same concentration?

Correct Answer
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What is the pH of a buffer that consists of 0.20 M NaH₂PO₄and 0.40 M Na₂HPO₄? For NaH₂PO₄,K_a = 6.2 × 10^-8

Correct Answer
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Calculate the solubility of lead(II) iodide, PbI₂, in 0.025 M KI. K_sp = 7.9 × 10^-9

Correct Answer
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Calculate the solubility of silver chromate, Ag₂CrO₄, in 0.005 M Na₂CrO₄. K_sp = 2.6 × 10^-12

Correct Answer
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Correct Answer
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If 10.0 g of NaF and 20.0 g of HF are dissolved in water to make one liter of solution, what will the pH be? For HF, K_a = 6.8 × 10^-4.

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

Correct Answer
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The solubility of silver chromate is 0.0287 g/1.0 L of solution. What is the K_sp for Ag₂CrO₄?

Correct Answer
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Exam 19: Ionic Equilibria in Aqueous Systems

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

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.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

A solution is prepared by dissolving 20.0 g of K2HPO4 and 25.0 g of KH2PO4 in enough water to produce 1.0 L of solution. What is the pH of this buffer? For phosphoric acid (H3PO4) , Ka2 = 6.2 × 10-8.

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

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 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?

Correct AnswerverifiedShow Answer

Silver phosphate, Ag3PO4, is an ionic compound with a solubility product constant Ksp of 2.6 × 10-18. Calculate the solubility of this compound in a. pure water. b. 0.20 mol L-1 Na3PO4 solution.

Correct Answerverifieda. 1.8 × 1...View AnswerShow 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

What is the pH of a buffer that consists of 0.45 M CH3COOH and 0.35 M CH3COONa? Ka = 1.8 × 10-5

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

Which one of the following is the best representation of the titration curve which will be obtained in the titration of a weak acid (0.10 mol L-1) with a strong base of the same concentration?

Correct AnswerverifiedShow Answer

What is the pH of a buffer that consists of 0.20 M NaH2PO4 and 0.40 M Na2HPO4? For NaH2PO4, Ka = 6.2 × 10-8

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

If 10.0 g of NaF and 20.0 g of HF are dissolved in water to make one liter of solution, what will the pH be? For HF, Ka = 6.8 × 10-4.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

The solubility of silver chromate is 0.0287 g/1.0 L of solution. What is the Ksp for Ag2CrO4?

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 Answer
verified

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.

Correct Answer
verified

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

Correct Answer
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A solution is prepared by dissolving 20.0 g of K₂HPO₄ and 25.0 g of KH₂PO₄ in enough water to produce 1.0 L of solution. What is the pH of this buffer? For phosphoric acid (H₃PO₄) , K_a2 = 6.2 × 10^-8.

Correct Answer
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Correct Answer
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Correct Answer
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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
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Correct Answer
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Silver phosphate, Ag₃PO₄, is an ionic compound with a solubility product constant K_sp of 2.6 × 10^-18. Calculate the solubility of this compound in a. pure water. b. 0.20 mol L^-1 Na₃PO₄ solution.

Correct Answer
verified
a. 1.8 × 1...
View Answer

Correct Answer
verified

What is the pH of a buffer that consists of 0.45 M CH₃COOH and 0.35 M CH₃COONa? K_a = 1.8 × 10^-5

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

Which one of the following is the best representation of the titration curve which will be obtained in the titration of a weak acid (0.10 mol L^-1) with a strong base of the same concentration?

Correct Answer
verified

What is the pH of a buffer that consists of 0.20 M NaH₂PO₄and 0.40 M Na₂HPO₄? For NaH₂PO₄,K_a = 6.2 × 10^-8

Correct Answer
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Calculate the solubility of lead(II) iodide, PbI₂, in 0.025 M KI. K_sp = 7.9 × 10^-9

Correct Answer
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Calculate the solubility of silver chromate, Ag₂CrO₄, in 0.005 M Na₂CrO₄. K_sp = 2.6 × 10^-12

Correct Answer
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Correct Answer
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If 10.0 g of NaF and 20.0 g of HF are dissolved in water to make one liter of solution, what will the pH be? For HF, K_a = 6.8 × 10^-4.

Correct Answer
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Correct Answer
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The solubility of silver chromate is 0.0287 g/1.0 L of solution. What is the K_sp for Ag₂CrO₄?

Correct Answer
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