Question 1

What is the pH of an aqueous solution that is 0.018 M C6H5NH2 (Kb = 4.3 * 10-10) and 0.12 M C6H5NH3Cl?

Accepted Answer

A)  5.46
B)  4.63
C)  3.81
D)  10.19
E)  8.54F) B) and E)
G) D) and E)

Question 2

Assuming no volume change on mixing,what mass of ammonium chloride should be added to 1.00 L of 0.250 M NH3(aq)to produce a buffer of pH 10.10? The molar mass of ammonium chloride is 53.49 g/mol.

Accepted Answer

Question 3

Choose the effective pH range of a HF/NaF buffer.For HF,Ka = 3.5 * 10-4.

Accepted Answer

A)  6.0-8.0
B)  9.6-11.6
C)  5.0-7.0
D)  0.7-2.7
E)  2.5-4.5F) A) and E)
G) A) and D)

Question 4

Consider the titration of 50.0 mL of 0.0200 M HClO(aq)with 0.100 M NaOH(aq).What is the formula of the main species in the solution after the addition of 10.0 mL of base?

Accepted Answer

ClO<sup>-</sup>

Question 5

When silver ions form a coordination complex with the thiosulfate ion,the latter acts as a Lewis acid.

Accepted Answer

A) True 
 B)False

Question 6

If a small amount of a strong acid is added to buffer made up of a weak acid,HA,and the sodium salt of its conjugate base,NaA,the pH of the buffer solution does not change appreciably because

Accepted Answer

A)  the Ka of HA is changed.
B)  the strong acid reacts with A- to give HA,which is a weak acid.
C)  no reaction occurs.
D)  the strong acid reacts with HA to give H2A+.
E)  the strong acid reacts with A- to give H2A+.F) B) and C)
G) A) and D)

Question 7

The pH of 0.30 M CH3NH2(aq)is 12.0.Therefore,the pH of a solution that is 0.30 M CH3NH2(aq)and 0.10 M CH3NH3Cl(aq)is greater than 12.0.

Accepted Answer

A) True 
 B)False

Question 8

Calculate the equilibrium constant for the reaction that occurs when nitric acid is added to the buffer HA(aq)/NaA(aq).The Ka of HA is 1.2 * 10-5.

Accepted Answer

8.3 * 10<s...

Question 9

Calculate the ratio of the molarities of HPO42- and H2PO4- ions required to achieve buffering at pH = 7.00.For H3PO4,pKa1 = 2.12,pKa2 = 7.21,and pKa3 = 12.68.

Accepted Answer

A)  0.81
B)  1.23
C)  0.62
D)  0.21
E)  1.62F) None of the above
G) All of the above C

Question 10

For HF,pKa = 3.45.What is the pH of an aqueous buffer solution that is 0.100 M HF(aq) and 0.300 M KF(aq) ?

Accepted Answer

A)  10.07
B)  2.97
C)  3.45
D)  3.93
E)  11.03F) B) and E)
G) B) and D)

Question 11

Which of the following mixtures gives a buffer with a pH less than 7.0? For acetic acid,Ka = 1.8 * 10-5 and for NH3,Kb = 1.8 * 10-5.

Accepted Answer

A)  10 mL of 0.1 M NH3(aq) + 10 ml of 0.1 M HCl(aq) 
B)  10 mL of 0.1 M aqueous acetic acid + 5.0 mL of 0.1 M NaOH(aq) 
C)  10 mL of 0.1 M aqueous acetic acid + 10 mL of 0.1 M NaOH(aq) 
D)  10 mL of 0.1 M aqueous acetic acid + 10 mL 0f 0.1 M NH3(aq) 
E)  10 mL of 0.1 M NH3(aq) + 5.0 mL of 0.1 M HCl(aq) F) D) and E)
G) A) and B)

Question 12

The pH of 0.50 M HNO2(aq)is 1.8.Therefore,the pH of a solution that is 0.50 M HNO2(aq)and 0.10 M KNO2(aq)is greater than 1.8.

Accepted Answer

A) True 
 B)False

Question 13

Choose the effective pH range of a pyridine/pyridinium chloride buffer? For pyridine,the value of Kb is 1.8 * 10-9.

Accepted Answer

A)  9.1-11.1
B)  1.4-3.4
C)  10.3-12.3
D)  7.7-9.7
E)  4.3-6.3F) D) and E)
G) C) and D)

Question 14

Calculate the ratio of the molarities of CO32- and HCO3- ions required to achieve buffering at pH = 9.0.For H2CO3,pKa1 = 6.37,and pKa2 = 10.00.

Accepted Answer

A)  0.50
B)  3.16
C)  1.65
D)  0.32
E)  0.61F) A) and D)
G) C) and D)

Question 15

What is the pH at the half-stoichiometric point for the titration of 0.88 M HNO2(aq) with 0.10 M KOH(aq) ? For HNO2,Ka = 4.3 * 10-4.

Accepted Answer

A)  3.37
B)  2.01
C)  1.86
D)  7.00
E)  1.71F) A) and D)
G) C) and D)

Question 16

If the molar solubility of the compound M2A3 is 7.0 * 10-6 M,what is the Ksp for this compound?

Accepted Answer

A)  1.7 * 10-26
B)  1.8 * 10-24
C)  2.9 * 10-10
D)  3.5 * 10-5E) A) and C)
F) All of the above B

Question 17

Silver bromide is most soluble in

Accepted Answer

A)  pure H2O(l) .
B)  dilute HNO3(aq) .
C)  0.10 M AgNO3(aq) .
D)  dilute NH3(aq) .
E)  0.10 M NaCl(aq) .F) B) and E)
G) A) and E)

Question 18

Which of the following indicators would be most suitable for the titration of 0.10 M lactic acid with 0.10 M KOH(aq) ? For lactic acid,pKa = 3.08.

Accepted Answer

A)  Methyl orange (pKIn = 3.4) 
B)  Thymol blue (pKIn = 1.7) 
C)  Alizarin yellow (pKIn = 11.2) 
D)  Bromophenol blue (pKIn = 3.9) 
E)  Phenol red (pKIn = 7.9) F) B) and C)
G) A) and E)

Question 19

What is the concentration of acetate ion at the stoichiometric point in the titration of 0.018 M CH3COOH(aq) with 0.072 M NaOH(aq) ? For acetic acid,Ka = 1.8 * 10-5.

Accepted Answer

A)  0.054 M
B)  0.036 M
C)  0.018 M
D)  0.072 M
E)  0.014 MF) None of the above
G) A) and D)

Question 20

For pyridine,pKb = 8.75.What is the pH of an aqueous buffer solution that is 0.300 M C5H5N(aq) and 0.500 M C5H5NHCl(aq) ?

Accepted Answer

A)  8.53
B)  5.25
C)  8.97
D)  5.47
E)  5.03F) B) and D)
G) C) and E)

Exam 13: Aqueous Equilibria

What is the pH of an aqueous solution that is 0.018 M C6H5NH2 (Kb = 4.3 * 10-10) and 0.12 M C6H5NH3Cl?

Correct AnswerverifiedShow Answer

Assuming no volume change on mixing,what mass of ammonium chloride should be added to 1.00 L of 0.250 M NH3(aq)to produce a buffer of pH 10.10? The molar mass of ammonium chloride is 53.49 g/mol.

Correct AnswerverifiedShow Answer

Choose the effective pH range of a HF/NaF buffer.For HF,Ka = 3.5 * 10-4.

Correct AnswerverifiedShow Answer

Consider the titration of 50.0 mL of 0.0200 M HClO(aq)with 0.100 M NaOH(aq).What is the formula of the main species in the solution after the addition of 10.0 mL of base?

Correct AnswerverifiedClO-

When silver ions form a coordination complex with the thiosulfate ion,the latter acts as a Lewis acid.

Correct AnswerverifiedShow Answer

If a small amount of a strong acid is added to buffer made up of a weak acid,HA,and the sodium salt of its conjugate base,NaA,the pH of the buffer solution does not change appreciably because

Correct AnswerverifiedShow Answer

The pH of 0.30 M CH3NH2(aq)is 12.0.Therefore,the pH of a solution that is 0.30 M CH3NH2(aq)and 0.10 M CH3NH3Cl(aq)is greater than 12.0.

Correct AnswerverifiedShow Answer

Calculate the equilibrium constant for the reaction that occurs when nitric acid is added to the buffer HA(aq)/NaA(aq).The Ka of HA is 1.2 * 10-5.

Correct Answerverified8.3 * 10View AnswerShow Answer

Calculate the ratio of the molarities of HPO42- and H2PO4- ions required to achieve buffering at pH = 7.00.For H3PO4,pKa1 = 2.12,pKa2 = 7.21,and pKa3 = 12.68.

Correct AnswerverifiedC

For HF,pKa = 3.45.What is the pH of an aqueous buffer solution that is 0.100 M HF(aq) and 0.300 M KF(aq) ?

Correct AnswerverifiedShow Answer

Which of the following mixtures gives a buffer with a pH less than 7.0? For acetic acid,Ka = 1.8 * 10-5 and for NH3,Kb = 1.8 * 10-5.

Correct AnswerverifiedShow Answer

The pH of 0.50 M HNO2(aq)is 1.8.Therefore,the pH of a solution that is 0.50 M HNO2(aq)and 0.10 M KNO2(aq)is greater than 1.8.

Correct AnswerverifiedShow Answer

Choose the effective pH range of a pyridine/pyridinium chloride buffer? For pyridine,the value of Kb is 1.8 * 10-9.

Correct AnswerverifiedShow Answer

Calculate the ratio of the molarities of CO32- and HCO3- ions required to achieve buffering at pH = 9.0.For H2CO3,pKa1 = 6.37,and pKa2 = 10.00.

Correct AnswerverifiedShow Answer

What is the pH at the half-stoichiometric point for the titration of 0.88 M HNO2(aq) with 0.10 M KOH(aq) ? For HNO2,Ka = 4.3 * 10-4.

Correct AnswerverifiedShow Answer

If the molar solubility of the compound M2A3 is 7.0 * 10-6 M,what is the Ksp for this compound?

Correct AnswerverifiedB

Silver bromide is most soluble in

Correct AnswerverifiedShow Answer

Which of the following indicators would be most suitable for the titration of 0.10 M lactic acid with 0.10 M KOH(aq) ? For lactic acid,pKa = 3.08.

Correct AnswerverifiedShow Answer

What is the concentration of acetate ion at the stoichiometric point in the titration of 0.018 M CH3COOH(aq) with 0.072 M NaOH(aq) ? For acetic acid,Ka = 1.8 * 10-5.

Correct AnswerverifiedShow Answer

For pyridine,pKb = 8.75.What is the pH of an aqueous buffer solution that is 0.300 M C5H5N(aq) and 0.500 M C5H5NHCl(aq) ?

Correct AnswerverifiedShow Answer

What is the pH of an aqueous solution that is 0.018 M C₆H₅NH₂ (K_b = 4.3 * 10^-10) and 0.12 M C₆H₅NH₃Cl?

Correct Answer
verified

Assuming no volume change on mixing,what mass of ammonium chloride should be added to 1.00 L of 0.250 M NH₃(aq)to produce a buffer of pH 10.10? The molar mass of ammonium chloride is 53.49 g/mol.

Correct Answer
verified

Choose the effective pH range of a HF/NaF buffer.For HF,K_a = 3.5 * 10^-4.

Correct Answer
verified

Correct Answer
verified
ClO^-

Correct Answer
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Correct Answer
verified

The pH of 0.30 M CH₃NH₂(aq)is 12.0.Therefore,the pH of a solution that is 0.30 M CH₃NH₂(aq)and 0.10 M CH₃NH₃Cl(aq)is greater than 12.0.

Correct Answer
verified

Calculate the equilibrium constant for the reaction that occurs when nitric acid is added to the buffer HA(aq)/NaA(aq).The K_a of HA is 1.2 * 10^-5.

Correct Answer
verified
8.3 * 10
View Answer

Calculate the ratio of the molarities of HPO₄^2- and H₂PO₄^- ions required to achieve buffering at pH = 7.00.For H₃PO₄,pK_a1 = 2.12,pK_a2 = 7.21,and pK_a3 = 12.68.

Correct Answer
verified
C

For HF,pK_a = 3.45.What is the pH of an aqueous buffer solution that is 0.100 M HF(aq) and 0.300 M KF(aq) ?

Correct Answer
verified

Which of the following mixtures gives a buffer with a pH less than 7.0? For acetic acid,K_a = 1.8 * 10^-5 and for NH₃,K_b = 1.8 * 10^-5.

Correct Answer
verified

The pH of 0.50 M HNO₂(aq)is 1.8.Therefore,the pH of a solution that is 0.50 M HNO₂(aq)and 0.10 M KNO₂(aq)is greater than 1.8.

Correct Answer
verified

Choose the effective pH range of a pyridine/pyridinium chloride buffer? For pyridine,the value of K_b is 1.8 * 10^-9.

Correct Answer
verified

Calculate the ratio of the molarities of CO₃²^- and HCO₃^- ions required to achieve buffering at pH = 9.0.For H₂CO₃,pK_a1 = 6.37,and pK_a2 = 10.00.

Correct Answer
verified

What is the pH at the half-stoichiometric point for the titration of 0.88 M HNO₂(aq) with 0.10 M KOH(aq) ? For HNO₂,K_a = 4.3 * 10^-4.

Correct Answer
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If the molar solubility of the compound M₂A₃ is 7.0 * 10^-⁶ M,what is the K_sp for this compound?

Correct Answer
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B

Correct Answer
verified

Which of the following indicators would be most suitable for the titration of 0.10 M lactic acid with 0.10 M KOH(aq) ? For lactic acid,pK_a = 3.08.

Correct Answer
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What is the concentration of acetate ion at the stoichiometric point in the titration of 0.018 M CH₃COOH(aq) with 0.072 M NaOH(aq) ? For acetic acid,K_a = 1.8 * 10^-5.

Correct Answer
verified

For pyridine,pK_b = 8.75.What is the pH of an aqueous buffer solution that is 0.300 M C₅H₅N(aq) and 0.500 M C₅H₅NHCl(aq) ?

Correct Answer
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