Deck 16: Additional Aqueous Equilibria Chemistry and the Oceans

Question 1

How many moles of sodium acetate must be added to 500.0 mL of 0.250 M acetic acid solution to produce a solution with a pH of 4.94? The pK_a of acetic acid is 4.74.)

A)0.011 moles
B)0.021 moles
C)0.13 moles
D)0.20 moles
E)0.21 moles

Answer 1

0.20 moles

Question 2

What reaction occurs as sodium hydroxide is added to a solution containing equal concentrations of acetic acid and sodium acetate?

A)CH₃ COOH(aq) + OH^-aq) $\rightarrow$ CH₃ COO^-(aq) + H₂ O(l)
B)CH₃ COO^-(aq) +H₂ Ol) $\rightarrow$ CH₃ COOH(aq) + OH^-(aq)
C)CH₃COO^-(aq) + Na⁺(aq) $\rightarrow$ NaCH₃COO(aq)
D)2 CH₃ COO^-(aq) + 2 OH^-(aq) $\rightarrow$ 2 CH₃ COOH(aq) + O₂ (g)
E)CH₃ COOH(aq) + Na⁺(aq) $\rightarrow$ NaCH₃ COO(aq) + H⁺(aq)

Answer 2

CH₃ COOH(aq) + OH^-aq) $\rightarrow$ CH₃ COO^-(aq) + H₂ O(l)

Question 3

A solution that contains a weak acid and its conjugate base in roughly equal concentrations is

A)neither acidic or basic.
B)a half-acid solution.
C)a buffer.
D)a heterogeneous mixture.
E)neutral.

Answer 3

a buffer.

Question 4

What is the pH of a solution prepared by dissolving 4.50 g sodium dihydrogen borate (83.82g/mol) in 650 mL of a 0.0725 M boric acid? The K_a of boric acid is 5.4 *10^-10.Ignore any volume change.

A)9.21
B)9.32
C)9.27
D)9.40
E)9.14

Question 5

Suppression of the solubility of one ion by the addition of the counter ion in its insoluble salt is known as the

A)ionic suppression effect.
B)counter-ion effect.
C)common-ion effect.
D)excession effect.
E)supersaturation effect.

Question 6

A solution containing roughly equal concentrations of is NOT a buffer solution.

A)fluoride ion and hydrofluoric acid
B)bromide ion and hydrobromic acid
C)phosphate ion and hydrogen phosphate ion
D)carbonate ion and hydrogen carbonate ion
E)phosphoric acid and dihydrogen phosphate ion

Question 7

A solution with a pH of 9.100 is prepared using aqueous ammonia and solid ammonium chloride.What is the ratio of [NH₃] to [NH₄⁺] in the solution? The K_b of ammonia is 1.76 * 10^-5.

A)0.850 to 1
B)1.02 to 1
C)0.984 to 1
D)1.41 to 1
E)0.715 to 1

Question 8

Consider the following aqueous equilibrium for a formic acid solution, HCOOH(aq) ⇄ H⁺(aq) + HCOO^-(aq).Suppose solid sodium hydroxide is added to the solution.Which statement below regarding the resulting solution is FALSE? Ignore any volume changes.

A)The pH increases.
B)The H⁺ concentration decreases.
C)The system shifts right to reestablish equilibrium.
D)The concentration of HCOO^- increases.
E)The value of K_a decreases.

Question 9

What is the pH of a solution in which [A^-] = 2[HA] and the pK_a of HA is 4.5?

A)2.5
B)4.2
C)4.5
D)4.8
E)6.5

Question 10

A buffer solution is made by dissolving 0.230 moles of sodium hypochlorite in 1.00 L of 0.220 M hypochlorous acid.What is the pH of the solution after 0.0100 moles of sodium hydroxide is added? (The K_a of HClO is 2.9 * 10^-8.)

A)6.520
B)6.404
C)7.578
D)7.480
E)7.596

Question 11

What is the pH of a solution prepared by mixing 550.0 mL of 0.703 M CH₃COOH with 460.0 mL of 0.905 M NaCH₃COO? The K_a of acetic acid is 1.76 *10^-5.Assume volumes are additive.

A)4.644
B)4.722
C)4.754
D)4.786
E)4.864

Question 12

Which solution below would make the best buffer? (Ac = acetate)

A)hydrochloric acid and sodium chloride, HCl and NaCl
B)acetic acid and ammonia, HAc and NH₃
C)acetic acid and ammonium chloride, HAc and NH₄Cl
D)sodium acetate and ammonium chloride, NaAc and NH₄Cl
E)ammonia and ammonium chloride, NH₃ and NH₄Cl

Question 13

Consider the following aqueous equilibrium for a formic acid solution, HCOOH(aq) ⇄ H⁺(aq) + HCOO^-(aq).Suppose solid sodium formate, NaHCOO, is added to the solution.Which of the following statements regarding the resulting solution is NOT correct? Ignore any volume changes.

A)The pH decreases.
B)The H⁺ concentration decreases.
C)The system shifts left to reestablish equilibrium.
D)The HCOOH concentration increases.
E)The value of K_a does not change.

Question 14

Consider the following aqueous equilibrium for a formic acid solution, HCOOH(aq) ⇄ H⁺(aq) + HCOO^-(aq).Suppose hydrogen chloride gas is dissolved in the solution.Which statement below regarding the resulting solution is FALSE? Ignore any volume changes.

A)The pH decreases.
B)The H⁺ concentration increases.
C)The system shifts left to reestablish equilibrium.
D)The concentration of HCOO^- decreases.
E)The value of K_a increases.

Question 15

To simulate the pH of blood, which is 7.4, a buffer solution made by dissolving sodium dihydrogen phosphate (K_a = 6.2 *10^-8) and sodium hydrogen phosphate (K_a= 3.6 *10^-13) together in an aqueous solution can be used.What mole ratio of Na₂HPO₄/NaH₂PO₄ is required to produce a solution with a pH of 7.4?

A)1.2
B)1.6
C)0.90
D)1.0
E)0.96

Question 16

What is the pH of a buffer solution in which [HA] = [A^-]?

A)pH =1
B)pH = K_a
C)pH = pK_a
D)pH = pOH
E)pH = 7.0

Question 17

Which of the statements below about an acid-base buffer solution is/are true?
I.It can be prepared by combining a strong acid with a salt of its conjugate base.
II.It can be prepared by combining a weak acid with a salt of its conjugate base.
III.It can be prepared by combining a weak base with its conjugate acid.
IV.The pH of a buffer solution does not change when the solution is diluted.
V.A buffer solution resists changes in its pH when an acid or base is added to it.

A)I, II, and IV
B)II, III, and V
C)II, III, IV, and V
D)I, II, IV, and V
E)II, III, and IV

Question 18

Research with biochemical systems commonly requires buffers because

A)it is less expensive to work at a constant pH.
B)proteins have a critical pH dependence in their structure and function.
C)proteins decompose into constituent amino acids outside a certain pH range.
D)proteins are buffers.
E)salts are involved.

Question 19

The pK_a of a weak acid was determined by measuring the pH of a solution containing the weak acid at 0.40 M and its conjugate base at 0.60 M.The measured pH was 7.8.What is the pK_a of the weak acid?

A)8.0
B)7.8
C)7.6
D)7.0
E)7.4

Question 20

Which pairs of substances below can be mixed together in water to produce a buffer solution?

A)HClO₄ and NaClO₄
B)HNO₃ and NaNO₃
C)H₂SO₄ and NaHSO₄
D)H₃PO₄ and NaH₂PO₄
E)HCl and NaCl

Question 21

At the equivalence point of a strong acid-strong base titration, which species are typically present?

A)a weakly acidic cation, a weakly basic anion, and water
B)a weakly acidic cation, a non-basic anion, and water
C)a non-acidic cation, a weakly basic anion, and water
D)a non-acidic cation, a non-basic anion, and water
E)All of these are equally possible.

Question 22

The following titration curve is most likely to be associated with

A)the titration of a strong acid with a strong base titrant.
B)the titration of a weak acid with a strong base titrant.
C)the titration of a strong base with a strong acid titrant.
D)the titration of a weak base with a strong acid titrant.

Question 23

In which of the following titrations would the solution be neutral at the equivalence point?

A)NH₃ titrated with HCl
B)SrOH)₂ titrated with H₃PO₄
C)HOCl titrated with BaOH)₂
D)CH₃COOH titrated with NaOH
E)HClO₄ titrated with KOH

Question 24

At what point in the following titration curve for a weak acid being titrated with a strong base is the pH equal to the pK_a of the acid? The x-axis scale goes from 0.0 mL to 20.0 mL.The sharp rise is at 10.0 mL.

A)0.0 mL
B)5.0 mL
C)9.0 mL
D)10.0 mL
E)18.0 mL

Question 25

What is true about the pK_a of the most suitable acid-base indicator for a titration of acetic acid with NaOH?

A)pK _a of the indicator =pK_a of the acid
B)pK _a of the indicator =pK_b of the base
C)pK _a of the indicator = pH of a sodium acetate solution
D)pK _a of the indicator = pH of an acetic acid solution
E)pK _a of the indicator = 7.0

Question 26

Acid-base indicators change color

A)exactly when pH = pK_a of the indicator.
B)generally over a range of 1 or 2 pH units.
C)at pH = 7.
D)always between a pH of 6 and 8.
E)at the midpoint of a titration.

Question 27

When an acetic acid solution is titrated with sodium hydroxide, the slope of the titration curve pH vs.volume of NaOH added) increases when sodium hydroxide is first added.This change shows that

A)nothing is happening during this part of the titration.
B)the reaction is very slow during this part of the titration.
C)a more concentrated solution of NaOH needs to be present to initiate the reaction.
D)acetic acid is being converted to sodium acetate.
E)the pH is not affected until all the acetic acid is consumed.

Question 28

What is true about the pK_a of the most suitable acid-base indicator for a titration of hydrochloric acid with NaOH?

A)pK_a of the indicator =pK_a of the acid
B)pK_a of the indicator = pK_b of the base
C)pK _a of the indicator =the concentration of the acid
D)pK _a of the indicator = the concentration of the base
E)pK _a of the indicator =7.0

Question 29

Phenylephrine (PE; see the structure below) is a nasal decongestant and is the active ingredient in Sudafed, which contains phenylephrine hydrochloride (PEHCl).This conjugate acid of phenylephrine (PEH⁺) has a pK_a= 5.5.At a physiological pH of 7.4, what is the ratio of concentrations, [PE]/[PEH⁺]?

A)6.7
B)0.01
C)0.14
D)79
E)21

Question 30

Which solution below would be the best choice for preparing a buffer with a pH =5.0?

A)formic acid and sodium formate, K_a = 1.8 * 10^-4
B)acetic acid and sodium acetate, K_a =1.8*10^-5
C)hypochlorous acid and sodium hypochlorite, K_a =3.5*10^-8
D)boric acid and sodium borate, K_a = 5.8 *10^-10
E)All of these solutions would be equally good choices for making this buffer.

Question 31

Halfway to the equivalence point in a titration curve of a weak acid with a strong base,

A)nothing is happening yet.
B)pH = pK_a of the weak acid.
C)pH = 3.5 exactly.
D)pH = pK_a of the indicator.
E)the pH has not yet changed.

Question 32

A buffer solution is made such that the initial concentrations of lactic acid (HC₃H₅O₃ ) and the lactate ion (C₃H₅O₃-) are 0.600 M and 0.620 M, respectively.What is the resulting pH if 100.0 mL of 0.100 M potassium hydroxide is added to 0.500 L of the buffer solution? (The K_a of HC₃H₅O₃ is 1.4 * 10^-4.)

A)3.81
B)3.90
C)2.75
D)4.96
E)3.85

Question 33

Which combination of solutions is the best choice for making a buffer solution?

A)equal volumes of 1 M ammonia NH₃) and 0.001 M ammonium chloride NH₄Cl)
B)equal volumes of 0.5 M hydrochloric acid HCl) and 0.5 M sodium hydroxide NaOH)
C)equal volumes of 0.5 M hydrochloric acid HCl) and 0.5 M sodium chloride NaCl)
D)equal volumes of 2 M ammonia NH₃) and 1 M hydrochloric acid HCl)
E)equal volumes of 2 M ammonium chloride NH₄Cl) and 1 M hydrochloric acid HCl)

Question 34

Acid-base indicators need to have very intense colors so that a very low concentration is visible.Could there be a problem in using too much indicator?

A)No, the colors would just be darker.
B)No, indicators are inert.
C)Yes, more indicator requires more extreme pH values to change color.
D)Yes, the indicator could affect the acid-base chemistry being measured.
E)No, the colors would just be sharper.

Question 35

What are the characteristics of a pH indicator? I.It is usually a conjugate acid-base pair.
II)It has different characteristic colors in protonated and unprotonated forms.
III)It changes color when the pH is near its pK_a.

A)I only
B)II only
C)both II and III
D)I, II, and III
E)I and III

Question 36

Which solution below would be the best choice for preparing a buffer with a pH=8.0?

A)formic acid and sodium formate, K_a =1.8 * 10^-4
B)acetic acid and sodium acetate, K_a = 1.8 *10^-5
C)hypochlorous acid and sodium hypochlorite, K_a = 3.5 *10^-8
D)boric acid and sodium borate, K_a =5.8 *10^-10
E)All of these solutions would be equally good choices for making this buffer.

Question 37

A buffer solution is made such that the initial concentrations of lactic acid (HC₃H₅O₃) and the lactate ion (C₃H₅O₃-) are both 0.600 M.What is the resulting pH if 10.0 mL of 1.00 M hydrochloric acid is added to 0.500 L of the buffer solution? (The K_a of HC₃H₅O₃ is 1.4 *10^-4.)

A)3.82
B)3.88
C)2.92
D)4.79
E)3.85

Question 38

Bromocresol green is yellow in its acidic form and blue in its basic form.When is it green?

A)at the equivalence point in a titration
B)in its neutral form
C)when the solution pH equals its pK_a
D)when the solution pH equals 7
E)at the midpoint in a titration

Question 39

A 25.00 mL sample of a hydrochloric acid solution was titrated to completion with 34.55 mL of 0.1020 M sodium hydroxide.What was the concentration of the hydrochloric acid?

A)0.07048 M
B)0.1410 M
C)0.2819 M
D)0.03524 M
E)0.05332 M

Question 40

In a titration of monoprotic acids and bases, there is a large change in pH

A)at the point where pH= pK_a of the acid.
B)when the volume of acid is exactly equal to the volume of base.
C)when the concentration of acid is exactly equal to the concentration of base.
D)when the number of moles of acid is exactly equal to the number of moles of base.
E)at the point at which pH = pK_b of the base.

Question 41

The following titration curve is most likely to be associated with

A)the titration of a strong acid with a strong base titrant.
B)the titration of a weak acid with a strong base titrant.
C)the titration of a strong base with a strong acid titrant.
D)the titration of a weak base with a strong acid titrant.

Question 42

Vitamin C is a monoprotic weak acid, which is also called ascorbic acid C₆H₈O₅, 176.12 g/mol).A vitamin C tablet weighing 0.75 g was dissolved in 50.0 mL of water and titrated with 0.250 M sodium hydroxide.It took 12.5 mL of the NaOH solution to reach the endpoint.What is the percentage of vitamin C in the tablet? Only the vitamin C reacted with the NaOH.

A)98.7%
B)64.2%
C)87.7%
D)95.5%
E)73.3%

Question 43

What is indicated by the shape of the titration curve?

A)A diprotic acid was titrated with a strong base.
B)A triprotic acid was titrated with a strong base.
C)A dibasic base was titrated with a strong acid.
D)A tribasic base was titrated with a strong acid.
E)A strong acid was titrated with a strong base.

Question 44

A 25.00 mL sample of a phosphoric acid solution was titrated to completion with 37.04 mL of 0.1107 M sodium hydroxide.What was the concentration of the phosphoric acid?

A)0.05467 M
B)0.08201 M
C)0.1640 M
D)0.3280 M
E)0.4920 M

Question 45

Suppose a 1.0 L solution containing 0.20 moles of propanoic acid is titrated with 0.40 M KOH.The pH at the equivalence point is 8.99.What is the K_a of propanoic acid?

A)1.4 *10 ^-5
B)2.1 * 10 ^-5
C)5.1 *10 ^-9
D)7.2*10 ^-9
E)Insufficient information is provided to determine K_a.

Question 46

Suppose a 1.0 L solution containing 0.20 moles of morphine is titrated with 0.40 M HCl.The pH at the equivalence point is 4.543.What is the K_b of morphine?

A)1.1*10 ^-6
B)9.4 -10 ^-9
C)1.6 - 10 ^-6
D)6.2 *10 ^-9
E)Insufficient information is provided to determine K_b.

Question 47

A Lewis acid is

A)a proton donor.
B)a proton acceptor.
C)an electron-pair donor.
D)an electron-pair acceptor.
E)never viewed also as a Brønsted-Lowry acid.

Question 48

Glycolic acid, which is a monoprotic acid and a constituent in sugarcane, has a pK_a of 3.9.A 25.0 mL solution of glycolic acid is titrated to the equivalence point with 35.8 mL of 0.020 M sodium hydroxide solution.What is the pH of the resulting solution at the equivalence point?

A)4.12
B)9.88
C)6.01
D)7.99
E)Insufficient information is provided to determine the pH.

Question 49

A Lewis base is any species capable of an electron pair.

A)accepting
B)donating
C)creating
D)neutralizing
E)gaining

Question 50

One brand of extra-strength antacid tablets contains 750 mg of calcium carbonate 100.09 g/mol) in each tablet.Stomach acid is essentially a hydrochloric acid solution.Is so much calcium carbonate really needed to neutralize stomach acid? Calculate the volume of stomach acid with a pH of 1.00 that one of these tablets could neutralize, and compare that value with the normal volume of stomach fluid, which usually is about 100.0 mL.One tablet can neutralize mL of stomach acid at a pH of 1.00.

A)75
B)150
C)250
D)15
E)7.5

Question 51

Identify the Lewis base in the following reaction: PH₃ (aq) +H⁺(aq) $\rightarrow$ PH₄⁺ (aq)

A)PH₄⁺
B)H⁺
C)PH₃
D)None of these is a base.
E)All of these are bases.

Question 52

Identify the Lewis acid in the following reaction: PH₃ (aq) +H⁺(aq) $\rightarrow$ PH₄⁺ (aq)

A)PH₄⁺
B)H⁺
C)PH₃
D)None of these is an acid.
E)All of these are acids.

Question 53

A phosphate buffer solution 25.00 mL sample) used for a growth medium was titrated with 0.1000 M hydrochloric acid.The components of the buffer were sodium monohydrogenphosphate and sodium dihydrogenphosphate.The first endpoint occurred at a volume of 10.32 mL, and the second occurred after an additional 18.62 mL was added, for a total volume of 28.94 mL.What was the total concentration of phosphate in any form) in the buffer?

A)0.03992 M
B)0.1198 M
C)0.04243 M
D)0.1157 M
E)0.08382 M

Question 54

A 25.0 mL solution of quinine was titrated with 1.00 M hydrochloric acid, HCl.It was found that the solution contained 0.125 moles of quinine.What was the pH of the solution after 50.00 mL of the HCl solution were added? Quinine is monobasic with pK_b = 5.10.

A)5.10
B)8.90
C)8.72
D)4.92
E)9.08

Question 55

A 0.500 g sample of an unknown substance was titrated with a 0.1 M HCl solution.Another 0.500 g sample of it was titrated with a 0.1 M NaOH solution.The resulting titration curves are illustrated here.Given the following possibilities, what is the sample?

A)Na₂CO₃
B)NaHCO₃
C)H₂CO₃
D)CO₂
E)There is no way to tell.

Question 56

A Lewis base is

A)an electron-pair acceptor.
B)an electron-pair donor.
C)a proton donor.
D)a proton acceptor.
E)never viewed also as a Brønsted-Lowry base.

Question 57

A solution of the weak acid, HF, and a solution of the strong acid, HCl, have the same pH.Which solution will require the most sodium hydroxide, NaOH, to neutralize?

A)HCl, because it is a strong acid and dissociates completely
B)HF, because its concentration is larger
C)Both will require the same amount because the concentrations are equal.
D)Both will require the same amount because the H₃O⁺ concentrations are the same.
E)HCl, because the stronger acid has the higher concentration

Question 58

A Lewis acid is any species capable of an electron pair.

A)accepting
B)donating
C)creating
D)neutralizing
E)losing

Question 59

Identify the Lewis base in the following reaction: SO₂ (g) +H₂ O(l) $\rightarrow$ H₂ SO₃ (aq)

A)SO₂
B)H₂O
C)H₂SO₃
D)None of these is a base.
E)All of these are bases.

Question 60

A 200.0 mL solution of 0.40 M ammonium chloride was titrated with 0.80M sodium hydroxide.What was the pH of the solution after 50.0 mL of the NaOH solution were added? The K_b of ammonia is 1.76 *10^-5.

A)9.25
B)4.75
C)11.22
D)5.02
E)8.98

Question 61

What is the equilibrium concentration of Cl ^- (aq) in a solution that is initially 0.0200 M solution in CuNO₃ and 0.450 M HCl(aq)?
Cu⁺(aq) + 3 Cl ^- 0(aq) fi CuCl₃^{2 -} (aq) K_f = 5.0 * 10⁵

A)0.450 M
B)2.0 * 10 ^{- 6} M
C)0.390 M
D)0.430 M
E)5 * 10⁵ M

Question 62

Which of the statements below regarding hydrated metal ions is FALSE?

A)An aqueous metal ion can attract the electrons in the O-H bonds of the water molecules in its inner coordination sphere.
B)Aqueous metal ions catalyze the autoionization of water, causing the solution to become more acidic.
C)In solutions that are slightly acidic to slightly basic, most aqueous transition metal ions exist as complexes in which at least one ligand is OH^-.
D)Acid strength typically increases as the charge on the aqueous metal ion increases.
E)Acid strength typically increases as the size of the aqueous metal ion decreases.

Question 63

What will be the equilibrium concentration of silver(I) ion in an aqueous solution originally containing 0.00100 M Ag⁺ and 0.500 M 1,10-phenanthroline?
Ag⁺(aq) + 2 phen(aq) fi [Ag(phen)₂ ]1⁺(aq) $\quad$ K_f = 1.2=10¹²

A)9.0 *10^-7 M
B)8.0 *10^-13 M
C)6.0 *10^-6 M
D)3.4 * 10^-15 M
E)1.2*10^-12 M

Question 64

Which of the following metal hydroxides is most likely to be more soluble in strongly basic solutions rather than weakly basic solutions?

A)MgOH)₂
B)PbOH)₂
C)CdOH)₂
D)AlOH)₃
E)FeOH)₃

Question 65

What is the pH of a 0.65 M (CuNO₃)₂ solution?
(K_a for Cu²⁺(aq) = 3.0 *10^-8

A)3.33
B)3.85
C)6.29
D)7.71
E)10.15

Question 66

What is the molar concentration of Ag⁺(aq) in a 1.00 M solution of Ag(NH₃)₂⁺ with no excess ammonia? (K_f = 1.70 * 10⁷ for Ag(NH₃)₂⁺)

A)2.45 *10^-3 M
B)3.09 * 10^-3 M
C)2.42 * 10^-4 M
D)1.47* 10^-8 M
E)1.70 * 10^-8 M

Question 67

For the reaction Fe(H₂O)₆³⁺(aq) +H₂O(l) ⇄ Fe(H₂O)₅(OH)²⁺(aq) +H₃O⁺(aq), Fe(H₂O)₆³⁺(aq) is a(n) _______ and water is a(n) _______.

A)base; acid
B)acid; base
C)acid; catalyst
D)catalyst; base
E)Lewis base; Lewis acid

Question 68

What is the equilibrium concentration of Cu⁺(aq) in a solution that is initially 0.0200 M solution in CuNO₃ and 0.450 M HCl(aq)?
Cu⁺(aq) + 3 Cl^-(aq) fi CuCl ^2-(aq) K_f * 5.0 *10⁵

A)5.0 F* 10⁵ M
B)1.0 * 10^-7 M
C)4.4 * 10^-7 M
D)5.0 * 10^-7 M
E)6.7 * 10^-7 M

Question 69

A coordinate covalent bond forms when a chemical species

A)donates one electron to another species to form a covalent bond.
B)accepts a pair of electrons and becomes an anion.
C)accepts one electron from another species to form a covalent bond.
D)accepts an electron and becomes an anion.
E)donates a pair of electrons to another species to form a covalent bond.

Question 70

Calculate the equilibrium concentration of ZN^{₂ +} (aq) in a solution that is initially 0.0125 M Zn(NO₃)₂ and 0.600 M NH₃.
Zn²⁺(aq) + 4 NH (aq) + Zn(NH₃)₄ ²⁺(aq) K_f = 2.9 * 10⁹

A)7.8 * 10^-12 M
B)4.7 * 10^- M
C)1.5 *10 ^{- 8} M
D)2.5 * 10 ^{- 9} M
E)2.9 * 10⁹ M

Question 71

What is the equilibrium concentration of ZN^₂+(aq) in a solution that is initially 0.0100 M solution in Zn(NO₃)₂ at a pH of 13.00?
Zn²⁺(aq) + 4 OH ^- (aq) fi Zn(OH)₄^{2 -} (aq) K_f=

A)3.1 * 10^-13 M
B)2.5 * 10^-14 M
C)4.4 * 10^-17 M
D)6.1* 10^-10 M
E)5.0 * 10⁵ M

Question 72

A ligand is any forming a coordinate bond to a metal cation.

A)Lewis acid
B)ion
C)Lewis base
D)organic compound
E)species

Question 73

What is the solubility of barium sulfate in a solution containing 0.050 M sodium sulfate? The K_sp value for barium sulfate is 1.1 *10^-10.

A)7.4 *10^-6 M
B)5.5 *10^-11 M
C)1.0 * 10^-5 M
D)2.2 *10^-9 M
E)1.1 * 10^-10 M

Question 74

When sodium chloride is added to a saturated solution of leadII) chloride, some of the leadII) chloride precipitates.This phenomenon is called

A)the common-ion effect.
B)selective precipitation.
C)supersaturation.
D)a solubility anomaly.
E)deionization.

Question 75

When NF₃ reacts with BF3 to form F₃NBF₃,

A)a complex ion is formed.
B)an ionic bond is formed.
C)the bond is formed by sharing an electron from NF₃ and an electron from BF₃.
D)a coordinate covalent bond is formed.
E)BF₃ donates an electron pair to NF₃.

Question 76

The solubility product for CaCO₃ is written as _______, where s is the molar solubility.

A)K_sp = s²
B)K_sp = 3s²
C)K_sp = S³
D)K_sp = 9s⁴
E)K_sp= 27s⁴

Question 77

Which statement below regarding complex ions and coordination compounds is FALSE?

A)Ligands function as electron pair donors.
B)A metal cation acts as a Lewis acid in a complex ion.
C)Ligands occupy the inner coordination sphere of the cation.
D)The information constant K_f for complex ions are generally much greater than 1.
E)Counter ions form coordinate covalent bonds with the ligands in a complex.

Question 78

Which of the following species is a Lewis base?

A)H⁺
B)Cs⁺
C)NF₃
D)NF₄⁺
E)NH₄⁺

Question 79

Which of the following salts, when dissolved in pure water, causes the greatest pH change?

A)BaCl₂
B)NaCl
C)CuCl₂
D)FeCl₃
E)ZnCl₂

Question 80

Hydrated transition metal ions typically produce solutions that are

A)acidic.
B)basic.
C)neutral.
D)strongly basic.
E)strongly acidic.