Chapter 15/14?- Additional aspects of aqueous equilibria

Question 1

Question

Which one of the following pairs cannot be mixed together to form a buffer solution?

Answer

A) HONH2, HONH3Cl
B) NaCl, HCl
C) RbOH, HF
D) KOH, HNO2
E) H2SO3, KHSO3

Question 2

Question

Which one of the following pairs cannot be mixed together to form a buffer solution?

Answer

A) NH3, NH4Cl
B) NaC2H3O2, HCl (C2H3O2- = acetate)
C) RbOH, HBr
D) KOH, HF
E) H3PO4, KH2PO4

Question 3

Question

A solution containing which one of the following pairs of substances will be a buffer solution?

Answer

A) NaI, HI
B) KBr, HBr
C) RbCl, HCl
D) CsF, HF
E) none of the above

Question 4

Question

What change will be caused by addition of a small amount of HCl to a solution containing fluoride ions and hydrogen fluoride?

Answer

A) The concentration of hydronium ions will increase significantly.
B) The concentration of fluoride ions will increase as will the concentration of hydronium ions.
C) The concentration of hydrogen fluoride will decrease and the concentration of fluoride ions will increase.
D) The concentration of fluoride ion will decrease and the concentration of hydrogen fluoride will increase.
E) The fluoride ions will precipitate out of solution as its acid salt.

Question 5

Question

In a solution, when the concentrations of a weak acid and its conjugate base are equal,

Answer

A) the system is not at equilibrium.
B) the buffering capacity is significantly decreased.
C) the -log of the [H+] and the -log of the Ka are equal.
D) all of the above are true.

Question 6

Question

Of the following solutions, which has the greatest buffering capacity?

Answer

A) 0.521 M HC2H3O2 and 0.217 M NaC2H3O2
B) 0.821 M HC2H3O2 and 0.713 M NaC2H3O2
C) 0.365M HC2H3O2 and 0.497 M NaC2H3O2
D) 0.121 M HC2H3O2 and 0.116 M NaC2H3O2

Question 7

Question

) Of the following solutions, which has the greatest buffering capacity?

Answer

A) 0.543 M NH3 and 0.555 M NH4Cl
B) 0.087 M NH3 and 0.088 M NH4Cl
C) 0.234 M NH3 and 0.100 M NH4Cl
D) 0.100 M NH3 and 0.455 M NH4Cl
E) They are all buffer solutions and would all have the same capacity.

Question 8

Question

The addition of hydrofluoric acid and __________ to water produces a buffer solution.

Answer

A) HCl
B) NaNO3
C) NaF
D) NaCl
E) NaBr

Question 9

Question

The addition of sodium hydroxide and __________ to water produces a buffer solution.

Answer

A) HCl
B) NaC2H3O2
C) NaF
D) NH3
E) none of the above

Question 10

Question

Which of the following could be added to a solution of potassium fluoride to prepare a buffer?

Answer

A) sodium hydroxide
B) potassium acetate
C) hydrochloric acid
D) sodium fluoride
E) ammonia

Question 11

Question

A 25.0 mL sample of a solution of an unknown compound is titrated with a 0.115 M NaOH solution. The titration curve above was obtained. The unknown compound is __________.

Image:

f4dd0893-d126-4e38-8321-7d44ad908a92 (image/png)

Answer

A) a strong acid
B) a strong base
C) a weak acid
D) a weak base

Question 12

Question

A 25.0 mL sample of a solution of a monoprotic acid is titrated with a 0.115 M NaOH solution. The titration curve above was obtained. The concentration of the monoprotic acid is about __________ mol/L.

Image:

bb849535-a4ed-4e25-b50c-81d5b5f7b3fe (image/png)

Answer

A) 25.0
B) 0.0600
C) 0.240
D) 0.120
E) 0.100

Question 13

Question

A 25.0 mL sample of a solution of a monoprotic acid is titrated with a 0.115 M NaOH solution. The titration curve above was obtained. Which of the following indicators would be best for this titration?

Image:

683e96ec-16a9-442d-bc4b-fd5a7caff662 (image/png)

Answer

A) methyl red
B) bromthymol blue
C) thymol blue
D) phenolpthalein
E) bromocresol purple

Question 14

Question

Which compound listed below has the greatest molar solubility in water?

Image:

3a05de4a-5592-4350-ba30-66f45e238e85 (image/png)

Answer

A) CdCO3
B) Cd(OH)2
C) AgI
D) CaF2
E) ZnCO3

Question 15

Question

The molar solubility of __________ is not affected by the pH of the solution.

Answer

A) Na3PO4
B) NaF
C) KNO3
D) ACl3
E) MnS

Question 16

Question

In which of the following aqueous solutions would you expect AgCl to have the lowest solubility?

Answer

A) pure water
B) 0.020 M BaCl2
C) 0.015 NaCl
D) 0.020 AgNO3
E) 0.020 KCl

Question 17

Question

In which one of the following solutions is silver chloride the most soluble?

Answer

A) 0.181 M HCl
B) 0.0176 M NH3
C) 0.744 M LiNO3
D) pure water
E) 0.181 M NaCl

Question 18

Question

Which below best describe(s) the behavior of an amphoteric hydroxide in water?

Answer

A) With conc. aq. NaOH, its suspension dissolves.
B) With conc. aq. HCl, its suspension dissolves.
C) With conc. aq. NaOH, its clear solution forms a precipitate.
D) With conc. aq. HCl, its clear solution forms a precipitate.
E) With both conc. aq. NaOH and conc. aq. HCl, its suspension dissolves.

Question 19

Question

A result of the common-ion effect is __________.

Answer

A) that some ions, such as Na+ (aq), frequently appear in solutions but do not participate in solubility equilibria
B) that common ions, such as Na+ (aq), don't affect equilibrium constants
C) that the selective precipitation of a metal ion, such as Ag+, is promoted by the addition of an appropriate counterion (X-) that produces a compound (AgX) with a very low solubility
D) that ions such as K+ and Na+ are common ions, so that their values in equilibrium constant expressions are always 1.00
E) that common ions precipitate all counter-ions

Question 20

Question

The Ka of benzoic acid is 6.30 × 10-5. The pH of a buffer prepared by combining 50.0 mL of 1.00 M potassium benzoate and 50.0 mL of 1.00 M benzoic acid is __________.

Answer

A) 1.705
B) 0.851
C) 3.406
D) 4.201
E) 2.383

Question 21

Question

Calculate the pH of a solution prepared by dissolving 0.150 mol of acetic acid and 0.300 mol of sodium acetate in water sufficient to yield 1.00 L of solution. The Ka of acetic acid is 1.76 × 10-5.

Answer

A) 2.516
B) 3.892
C) 4.502
D) 10.158
E) 5.056

Question 22

Question

The pH of a solution prepared by dissolving 0.350 mol of solid methylamine hydrochloride (CH3NH3Cl) in 1.00 L of 1.10 M methylamine (CH3NH2) is __________. The Kb for methylamine is 4.40 × 10-4. (Assume the final volume is 1.00 L.)

Answer

A) 1.66
B) 2.86
C) 10.28
D) 11.14
E) 10.61

Question 23

Question

A 25.0 mL sample of 0.723 M HClO4 is titrated with a 0.27 M KOH solution. The H3O+ concentration after the addition of 80.0 mL of KOH is __________ M.

Answer

A) 0.0333
B) 1 × 10-7
C) 0.7
D) 3 × 10-13
E) 4 × 10-2

Question 24

Question

The pH of a solution prepared by mixing 50.0 mL of 0.125 M KOH and 50.0 mL of 0.125 M HCl is __________.

Answer

A) 6.29
B) 7.00
C) 8.11
D) 5.78
E) 0.00

Question 25

Question

The pH of a solution prepared by mixing 40.0 mL of 0.125 M Mg(OH)2 and 150.0 mL of 0.125 M HCl is __________.

Answer

A) 6.29
B) 4.11
C) 1.14
D) 5.78
E) 1.34

Question 26

Question

The pH of a solution prepared by mixing 50.0 mL of 0.125 M NaOH and 40.0 mL of 0.125 M HNO3 is __________.

Answer

A) 13.29
B) 7.00
C) 8.11
D) 11.00
E) none of the above

Question 27

Question

A 50.0 mL sample of an aqueous H2SO4 solution is titrated with a 0.375 M NaOH solution. The equivalence point is reached with 62.5 mL of the base. The concentration of H2SO4 is __________ M.

Answer

A) 0.234
B) 0.469
C) 0.150
D) 0.300
E) 0.938

Question 28

Question

The concentration of iodide ions in a saturated solution of lead (II) iodide is __________ M. The solubility product constant of PbI2 is 1.4 × 10-8.

Answer

A) 3.8 × 10-4
B) 3.0 × 10-3
C) 1.5 × 10-3
D) 3.5 × 10-9
E) 1.4 × 10-8

Question 29

Question

Calculate the percent ionization of formic acid (HCO2H) in a solution that is 0.311 M in formic acid and 0.189 M in sodium formate (NaHCO2). The Ka of formic acid is 1.77 × 10-4.

Answer

A) 37.8
B) 0.0937
C) 11.3
D) 1.06 × 10-3
E) 3.529

Question 30

Question

A solution is prepared by dissolving 0.23 mol of hydrofluoric acid and 0.27 mol of sodium fluoride in water sufficient to yield 1.00 L of solution. The addition of 0.05 mol of HCl to this buffer solution causes the pH to drop slightly. The pH does not decrease drastically because the HCl reacts with the __________ present in the buffer solution. The Ka of hydrofluoric acid is 1.36 × 10-3.

Answer

A) H2O
B) H3O+
C) fluoride ion
D) hydrofluoric acid
E) This is a buffer solution: the pH does not change upon addition of acid or base.

Question 31

Question

A solution is prepared by dissolving 0.23 mol of hydrazoic acid and 0.27 mol of sodium azide in water sufficient to yield 1.00 L of solution. The addition of 0.05 mol of NaOH to this buffer solution causes the pH to increase slightly. The pH does not increase drastically because the NaOH reacts with the __________ present in the buffer solution. The Ka of hydrazoic acid is 1.9 × 10-5.

Answer

A) H2O
B) H3O+
C) azide
D) hydrazoic acid
E) This is a buffer solution: the pH does not change upon addition of acid or base.

Question 32

Question

Consider a solution containing 0.100 M fluoride ions and 0.126 M hydrogen fluoride. The concentration of fluoride ions after the addition of 4.00 mL of 0.0100 M HCl to 25.0 mL of this solution is __________ M.

Answer

A) 0.0862
B) 0.0876
C) 0.0980
D) 0.0848
E) 0.00253

Question 33

Question

The Ka of acetic acid is 1.76 × 10-5. The pH of a buffer prepared by combining 45.0 mL of 1.00 M potassium acetate and 50.0 mL of 1.00 M acetic acid is __________.

Answer

A) 1.705
B) 0.851
C) 3.406
D) 4.709
E) 2.383

Question 34

Question

The Kb of ammonia is 1.76 × 10-5. The pH of a buffer prepared by combining 50.0 mL of 1.00 M ammonia and 50.0 mL of 1.00 M ammonium nitrate is __________.

Answer

A) 4.632
B) 9.246
C) 4.742
D) 9.372
E) none of the above

Question 35

Question

How many milliliters of 0.0850 M NaOH are required to titrate 25.0 mL of 0.0720 M HBr to the equivalence point?

Answer

A) 21.2
B) 0.245
C) 3.92
D) 0.153
E) 29.5

Question 36

Question

A 25.0 mL sample of 0.150 M hydrazoic acid is titrated with a 0.150 M NaOH solution. What is the pH at the equivalence point? The Ka of hydrazoic acid is 4.50 × 10-4.

Answer

A) 11.72
B) 9.28
C) 4.72
D) 7.00
E) 8.80

Question 37

Question

A 25.0-mL sample of 0.150 M butanoic acid is titrated with a 0.150 M NaOH solution. What is the pH before any base is added? The Ka of butanoic acid is 1.5 × 10-5.

Answer

A) 2.83
B) 1.5 × 10-3
C) 4.82
D) 4.00
E) 1.0 × 104

Question 38

Question

A 25.0 mL sample of 0.150 M hypochlorous acid is titrated with a 0.150 M NaOH solution. What is the pH after 26.0 mL of base is added? The Ka of hypochlorous acid is 3.0 × 10-8.

Answer

A) 2.54
B) 11.47
C) 7.00
D) 7.51
E) 7.54

Question 39

Question

A 25.0-mL sample of 0.150 M hydrazoic acid is titrated with a 0.150 M NaOH solution. What is the pH after 13.3 mL of base is added? The Ka of hydrazoic acid is 1.9 × 10-5.

Answer

A) 4.45
B) 1.34
C) 3.03
D) 4.78
E) 4.66

Question 40

Question

A 25.0 mL sample of 0.723 M HClO4 is titrated with a 0.273 M KOH solution. The H3O+ concentration after the addition of 60.0 mL of KOH is __________ M.

Answer

A) 0.0181
B) 0.430
C) 0.0200
D) 0.273
E) none of the above

Question 41

Question

The pH of a solution prepared by mixing 45.0 mL of 0.183 M KOH and 25.0 mL of 0.145 M HCl is __________.

Answer

A) 1.314
B) 1.181
C) 0.00824
D) 12.819
E) 12.923

Question 42

Question

In which aqueous system is Pbl2 least soluble?

Answer

A) H2O
B) 0.5 M HI
C) 0.2 M HI
D) 1.0 M HNO3
E) 0.8 M KI

Question 43

Question

Suppose you have just added 100.0 ml of a solution containing 0.5000 moles of acetic acid per liter to 400.0 ml of 0.5000 M NaOH. What is the final pH? The Ka of acetic acid is 1.77 × 10-5.

Answer

A) 9.123
B) 4.877
C) 0.5229
D) 13.48

Question 44

Question

An assembly of a metal ion and the Lewis bases bonded to it is called a __________.

Answer

A) Complex Ion
B) Lewis Structure
C) Soluble compound

Question 45

Question

Metal oxides and hydroxides that are relatively insoluble in neutral water, but are soluble in both strongly acidic and strongly basic solutions are said to be __________.

Answer

A) amphiprotic
B) amphoteric
C) amphiphilic
D) amphipathic

	Created by Dawn G over 7 years ago

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Chapter 15/14?- Additional aspects of aqueous equilibria

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