Question 1

When a weak acid is titrated with a strong 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 14.0 - pKb, where pKb is that of the base.F) A) and E)
G) None of the above

Question 2

Which of the following substances has the greatest solubility in water?

Accepted Answer

A)   Ba(IO3) 2, Ksp = 1.5 *10¯9
B)   PbF2, Ksp = 3.6 *10¯8
C)   SrSO4, Ksp = 3.2 * 10¯7
D)   CuCl, Ksp = 1.9 * 10¯7
E)   CdS, Ksp = 1.0 * 10¯24F) A) and B)
G) A) and C)

Question 3

Equal volumes of the following pairs of solutions are mixed. Which pair will produce a buffer solution?

Accepted Answer

A)   0.10 mol L¯1 HCl and 0.05 mol L¯1 NaOH
B)   0.10 mol L¯1 HCl and 0.15 mol L¯1 NH3
C)   0.10 mol L¯1 HCl and 0.05 mol L¯1 NH3
D)   0.10 mol L¯1 HCl and 0.20 mol L¯1 CH3COOH
E)   0.10 mol L¯1 HCl and 0.20 mol L¯1 NaClF) B) and E)
G) B) and D)

Question 4

The solubility of magnesium phosphate is 2.27 * 10¯3 g/1.0 L of solution. What is the Ksp for Mg3(PO4) 2?

Accepted Answer

A)   6.5 * 10¯12
B)   6.0 *10¯14
C)   5.2 *10¯24
D)   4.8* 10¯26
E)   1.0 * 10¯26F) B) and D)
G) A) and B)

Question 5

A phosphate buffer (H2PO4¯/HPO42¯)  has a pH of 8.3. Which of the following changes will cause the pH to increase?

Accepted Answer

A)   dissolving a small amount of Na2HPO4
B)   dissolving a small amount of NaH2PO4
C)   adding a small amount of dilute hydrochloric acid
D)   adding a small amount of dilute phosphoric acid
E)   making the buffer more concentrated by removing some waterF) A) and E)
G) B) and C)

Question 6

Which of the following substances has the greatest solubility in water?

Accepted Answer

A)   PbI2, Ksp = 7.9 *10¯9
B)   BaF2, Ksp = 1.5 * 10¯6
C)   Ca(OH) 2, Ksp = 6.5 *10¯6
D)   Zn(IO3) 2, Ksp = 3.9 * 10¯6
E)   Ag2SO4, Ksp = 1.5 *10¯5F) None of the above
G) C) and D) E

Question 7

For a diprotic acid H2A, the relationship Ka1 > Ka2 is always true.

Accepted Answer

A) True 
 B)False  True

Question 8

The solubility of lead(II)  chloride is 0.45 g/100 mL of solution. What is the Ksp of PbCl2?

Accepted Answer

A)   4.9 * 10¯2
B)   1.7 * 10¯5
C)   8.5 * 10¯6
D)   4.2 * 10¯6
E)   6F) A) and B)
G) A) and E) B

Question 9

A sample of a monoprotic acid (HA)  weighing 0.384 g is dissolved in water and the solution is titrated with aqueous NaOH. If 30.0 mL of 0.100 M NaOH is required to reach the equivalence point, what is the molar mass of HA?

Accepted Answer

A)   37.0 g/mol
B)   81.0 g/mol
C)   128 g/mol
D)   20.3 g/mol
E)   211 g/molF) None of the above
G) A) and C)

Question 10

What is the pH of a solution that consists of 0.50 M H2C6H6O6 (ascorbic acid)  and 0.75 M NaHC6H6O6 (sodium ascorbate) ? For ascorbic acid, Ka = 6.8 *10¯5

Accepted Answer

A)   3.76
B)   3.99
C)   4.34
D)   4.57
E)   5.66F) A) and B)
G) A) and E)

Question 11

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 *0 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 C)
G) A) and E)

Question 12

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)   13.14F) B) and E)
G) C) and D)

Question 13

Assuming that the total volume does not change after 0.200 g of KCl is added to 1.0 L of a saturated aqueous solution of AgCl, calculate the number of moles of Ag+ ion in the solution after equilibrium has been reestablished. For AgCl, Ksp = 1.8 *10¯10

Accepted Answer

A)   1.8 * 10¯10 mol Ag+
B)   9.0 * 10¯10 mol Ag+
C)   9.0 * 10¯9 mol Ag+
D)   6.7 *10¯8 mol Ag+
E)   1.3 *10¯5 mol Ag+F) A) and C)
G) None of the above

Question 14

Which one of the following pairs of 0.100 mol L¯1 solutions, when mixed, will produce a buffer solution?

Accepted Answer

A)   50. mL of aqueous CH3COOH and 25. mL of aqueous HCl
B)   50. mL of aqueous CH3COOH and 100. mL of aqueous NaOH
C)   50. mL of aqueous NaOH and 25. mL of aqueous HCl
D)   50. mL of aqueous CH3COONa and 25. mL of aqueous NaOH
E)   50. mL of aqueous CH3COOH and 25. mL of aqueous CH3COONaF) A) and D)
G) D) and E)

Question 15

When a strong acid is titrated with a strong 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, but is not 3.5.
D)   is equal to the pKa of the acid.
E)   is equal to 3.5.F) All of the above
G) A) and E)

Question 16

When 20.0 mL of 0.15 M hydrochloric acid is mixed with 20.0 mL of 0.10 M sodium hydroxide, the pH of the resulting solution is

Accepted Answer

A)   0.00
B)   12.40
C)   1.60
D)   0.82
E)   7.00F) A) and B)
G) A) and C)

Question 17

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 choices is correct.F) B) and D)
G) A) and B)

Question 18

Calculate the solubility of barium carbonate, BaCO3, in pure water. Ksp = 2.0 *10¯9

Accepted Answer

A)   1.3 * 10¯3 M
B)   3.2 * 10¯5 M
C)   2.2 * 10¯5 M
D)   4.5 *10¯5 M
E)   4.0 * 10¯18 MF) None of the above
G) D) and E)

Question 19

You need to prepare a buffer solution with a pH of 4.00, using NaF and HF. What ratio of the ratio of [base]/[acid] should be used in making the buffer? For HF, Ka = 7.2 * 10¯4

Accepted Answer

A)   [base]/[acid] = 0.14
B)   [base]/[acid] = 0.42
C)   [base]/[acid] = 2.36
D)   [base]/[acid] = 7.20
E)   None of these choices is correct.F) B) and C)
G) None of the above

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 these choices is correct.F) All of the above
G) A) and B)

Exam 19: Ionic Equilibria in Aqueous Systems

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

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Which of the following substances has the greatest solubility in water?

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Equal volumes of the following pairs of solutions are mixed. Which pair will produce a buffer solution?

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The solubility of magnesium phosphate is 2.27 * 10¯3 g/1.0 L of solution. What is the Ksp for Mg3(PO4) 2?

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A phosphate buffer (H2PO4¯/HPO42¯) has a pH of 8.3. Which of the following changes will cause the pH to increase?

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Which of the following substances has the greatest solubility in water?

Correct AnswerverifiedE

For a diprotic acid H2A, the relationship Ka1 > Ka2 is always true.

Correct AnswerverifiedTrue

The solubility of lead(II) chloride is 0.45 g/100 mL of solution. What is the Ksp of PbCl2?

Correct AnswerverifiedB

A sample of a monoprotic acid (HA) weighing 0.384 g is dissolved in water and the solution is titrated with aqueous NaOH. If 30.0 mL of 0.100 M NaOH is required to reach the equivalence point, what is the molar mass of HA?

Correct AnswerverifiedShow Answer

What is the pH of a solution that consists of 0.50 M H2C6H6O6 (ascorbic acid) and 0.75 M NaHC6H6O6 (sodium ascorbate) ? For ascorbic acid, Ka = 6.8 *10¯5

Correct AnswerverifiedShow Answer

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

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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?

Correct AnswerverifiedShow Answer

Assuming that the total volume does not change after 0.200 g of KCl is added to 1.0 L of a saturated aqueous solution of AgCl, calculate the number of moles of Ag+ ion in the solution after equilibrium has been reestablished. For AgCl, Ksp = 1.8 *10¯10

Correct AnswerverifiedShow Answer

Which one of the following pairs of 0.100 mol L¯1 solutions, when mixed, will produce a buffer solution?

Correct AnswerverifiedShow Answer

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

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When 20.0 mL of 0.15 M hydrochloric acid is mixed with 20.0 mL of 0.10 M sodium hydroxide, the pH of the resulting solution is

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

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Calculate the solubility of barium carbonate, BaCO3, in pure water. Ksp = 2.0 *10¯9

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You need to prepare a buffer solution with a pH of 4.00, using NaF and HF. What ratio of the ratio of [base]/[acid] should be used in making the buffer? For HF, Ka = 7.2 * 10¯4

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

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The solubility of magnesium phosphate is 2.27 * 10¯³ g/1.0 L of solution. What is the K_sp for Mg₃(PO₄) ₂?

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A phosphate buffer (H₂PO₄¯/HPO₄²¯) has a pH of 8.3. Which of the following changes will cause the pH to increase?

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E

For a diprotic acid H₂A, the relationship K_a1 > K_a2 is always true.

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True

The solubility of lead(II) chloride is 0.45 g/100 mL of solution. What is the K_sp of PbCl₂?

Correct Answer
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B

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What is the pH of a solution that consists of 0.50 M H₂C₆H₆O₆ (ascorbic acid) and 0.75 M NaHC₆H₆O₆ (sodium ascorbate) ? For ascorbic acid, K_a = 6.8 *10¯⁵

Correct Answer
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Assuming that the total volume does not change after 0.200 g of KCl is added to 1.0 L of a saturated aqueous solution of AgCl, calculate the number of moles of Ag⁺ ion in the solution after equilibrium has been reestablished. For AgCl, K_sp = 1.8 *10¯¹⁰

Correct Answer
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Which one of the following pairs of 0.100 mol L¯¹ solutions, when mixed, will produce a buffer solution?

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Calculate the solubility of barium carbonate, BaCO₃, in pure water. K_sp = 2.0 *10¯⁹

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You need to prepare a buffer solution with a pH of 4.00, using NaF and HF. What ratio of the ratio of [base]/[acid] should be used in making the buffer? For HF, K_a = 7.2 * 10¯⁴

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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