Chemistry, 6e (McMurry/Fay)Chapter 15 Applications of Aqueous Equilibria

15.1 Multiple-Choice Questions

1) Which is a net ionic equation for the neutralization of a strong acid with a strong base?A) HCl(aq) + NaOH(aq) ⇌ H2O(l) + NaCl(aq)

B) H3O+(aq) + OH-(aq) ⇌ 2 H2O(l)C) HF(aq) + NaOH(aq) ⇌ H2O(l) + NaF(aq)

D) HF(aq) + OH-(aq) ⇌ H2O(l) + F-(aq)Answer: BTopic: Section 15.1 Neutralization Reactions

2) Which is a net ionic equation for the neutralization of a weak acid with a strong base?A) HCl(aq) + NaOH(aq) ⇌ H2O(l) + NaCl(aq)

B) H3O+(aq) + OH-(aq) ⇌ 2 H2O(l)C) HF(aq) + NaOH(aq) ⇌ H2O(l) + NaF(aq)

D) HF(aq) + OH-(aq) ⇌ H2O(l) + F-(aq)Answer: DTopic: Section 15.1 Neutralization Reactions

3) Which is a net ionic equation for the neutralization reaction of a strong acid with a weak base?A) HCl(aq) + NaOH(aq) ⇌ H2O(l) + NaCl(aq)

B) H3O+(aq) + OH-(aq) ⇌ 2 H2O(l)C) HCl(aq) + NH3(aq) ⇌ NH4Cl(aq)

D) H3O+(aq) + NH3(aq) ⇌ NH4+(aq) + H2O(l)Answer: DTopic: Section 15.1 Neutralization Reactions

4) Which is a net ionic equation for the neutralization reaction of a weak acid with a weak base?A) H3O+(aq) + OH-(aq) ⇌ 2 H2O(l)

B) HF(aq) + NH3(aq) ⇌ NH4+(aq) + F-(aq)

C) HF(aq) + OH-(aq) ⇌ H2O(l) + F-(aq)

D) H3O+(aq) + NH3(aq) ⇌ NH4+(aq) + H2O(l)Answer: BTopic: Section 15.1 Neutralization Reactions

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5) What is the equation relating the equilibrium constant Kn for the neutralization of a weak acid with a weak base to the Ka of the acid, the Kb of the base and Kw?A) Kn = KaKbKw

B) Kn =

C) Kn =

D) Kn =

Answer: BTopic: Section 15.1 Neutralization Reactions

6) What is the approximate value of the equilibrium constant, Kn, for the neutralization of acetic acid

with sodium hydroxide, shown in the equation below? The Ka for acetic acid is 1.8 × 10–5.CH3CO2H(aq) + NaOH(aq) ⇌ H2O(l) + NaCH3CO2(aq)

A) 1.8 × 10-19

B) 5.6 × 10-10

C) 1.8 × 10-8

D) 1.8 × 109Answer: DTopic: Section 15.1 Neutralization Reactions

7) What is the approximate value of the equilibrium constant, Kn, for the neutralization of pyridine with

hydrochloric acid, shown in the equation below? The Kb for pyridine is 1.8 × 10–9.HCl(aq) + C5H5N(aq) ⇌ C5H5NHCl(aq)

A) 5.6 × 10-10

B) 5.6 × 10-6

C) 1.8 × 105

D) 5.6 × 108Answer: CTopic: Section 15.1 Neutralization Reactions

8) What is the approximate value of the equilibrium constant, Kn, for the neutralization of nitrous acid

with ammonia, shown in the equation below? The Ka for HNO2 is 4.5 × 10–4 and the Kb for NH3 is

1.8 × 10–5. HNO2(aq) + NH3(aq) ⇌ NH4NO2(aq)

A) 8.1 × 105

B) 1.8 × 109

C) 4.5 × 1010

D) 8.1 × 1019Answer: ATopic: Section 15.1 Neutralization Reactions

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9) What is the approximate value of the equilibrium constant, Kn, for the neutralization of hydrochloric acid with sodium hydroxide, shown in the equation below?

HCl(aq) + NaOH(aq) ⇌ H2O(l) + NaCl(aq)

A) 1.0 × 102

B) 1.0 × 107

C) 1.0 × 1014

D) 1.0 × 1028Answer: CTopic: Section 15.1 Neutralization Reactions

10) The neutralization constant Kn for the neutralization of acetylsalicylic acid (C9H8O4) and codeine

(C18H21NO3) is 4.8 × 104. The acid dissociation constant Ka for acetylsalicylic acid is 3.0 × 10-4. What is the base dissociation constant Kb for codeine?

A) 4.8 × 10-24

B) 6.3 × 10-23

C) 1.6 × 10-6

D) 1.4 × 1015Answer: CTopic: Section 15.1 Neutralization Reactions

11) The neutralization constant Kn for the neutralization of phenobarbital (C12H12N2O3) and morphine

(C17H19NO3) is 2.9. The acid dissociation constant Ka for phenobarbital is 3.9 × 10-8. What is the base dissociation constant Kb for morphine?

A) 1.3 × 10-22

B) 6.3 × 10-23

C) 7.4 × 10-7

D) 1.1 × 107Answer: CTopic: Section 15.1 Neutralization Reactions

12) Which of these neutralization reactions has a pH = 7 when equal molar amounts of acid and base are mixed?A) CH3CO2H(aq) + NaOH(aq) ⇌ H2O(l) + NaCH3CO2(aq)B) HCl(aq) + C5H5N(aq) ⇌ C5H5NHCl(aq)C) HCl(aq) + NaOH(aq) ⇌ H2O(l) + NaCl(aq)D) HNO2(aq) + NH3(aq) ⇌ NH4NO2(aq)Answer: CTopic: Section 15.1 Neutralization Reactions

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13) Which of these neutralization reactions has a pH < 7 when equal molar amounts of acid and base are mixed?A) CH3CO2H(aq) + NaOH(aq) ⇌ H2O(l) + NaCH3CO2(aq)B) HCl(aq) + C5H5N(aq) ⇌ C5H5NHCl(aq)C) HCl(aq) + NaOH(aq) ⇌ H2O(l) + NaCl(aq)D) H2SO4(aq) + 2 KOH(aq) ⇌2 H2O(l) + K2SO4(aq)Answer: BTopic: Section 15.1 Neutralization Reactions

14) Which of these neutralization reactions has a pH > 7 when equal moles of acid and base are mixed?A) CH3CO2H(aq) + NaOH(aq) ⇌ H2O(l) + NaCH3CO2(aq)B) HCl(aq) + C5H5N(aq) ⇌ C5H5NHCl(aq)C) HCl(aq) + NaOH(aq) ⇌ H2O(l) + NaCl(aq)D) H2SO4(aq) + 2 KOH(aq) ⇌2 H2O(l) + K2SO4(aq)Answer: ATopic: Section 15.1 Neutralization Reactions

15) What is the common ion in a solution prepared by mixing 0.10 M NaCH3CO2 with 0.10 M CH3CO2H?

A) H3O+

B) Na+

C) CH3CO2-

D) OH-Answer: CTopic: Section 15.2 The Common-Ion Effect

16) When 50 mL of 0.10 M NH4Cl is added to 50 mL of 0.10 M NH3, relative to the pH of the 0.10 M NH3 solution the pH of the resulting solution willA) become 7.B) decrease.C) increase.D) remain the same.Answer: BTopic: Section 15.2 The Common-Ion Effect

17) When 50 mL of 0.10 M NaF is added to 50 mL of 0.10 M HF, relative to the pH of the 0.10 M HF solution the pH of the resulting solution willA) become 7.B) decrease.C) increase.D) remain the same.Answer: CTopic: Section 15.2 The Common-Ion Effect

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18) What is the hydronium ion concentration in a solution prepared by mixing 50.00 mL of 0.10 M HCN

with 50.00 mL of NaCN? Assume that the volumes of the solutions are additive and that Ka =

4.9 × 10-10 for HCN.A) 2.4 × 10-10 MB) 4.9 × 10-10 MC) 9.8 × 10-10 MD) 7.0 × 10-6 MAnswer: CTopic: Section 15.2 The Common-Ion Effect

19) What is the pH of a solution prepared by mixing 25.00 mL of 0.10 M CH3CO2H with 25.00 mL of

0.050 M CH3CO2Na? Assume that the volume of the solutions are additive and that Ka = 1.8 × 10-5 for CH3CO2H.A) 2.87B) 4.44C) 4.74D) 5.05Answer: BTopic: Section 15.2 The Common-Ion Effect

20) What is the pH of a solution prepared by mixing 50.00 mL of 0.10 M NH3 with 25.00 mL of 0.10 M

NH4Cl? Assume that the volume of the solutions are additive and that Kb = 1.8 × 10-5 for NH3.A) 8.95B) 9.26C) 9.56D) 11.13Answer: CTopic: Section 15.2 The Common-Ion Effect

21) What is the pH of a solution prepared by mixing 25.00 mL of 0.10 M methylamine, CH3NH2, with 25.00 mL of 0.10 M methylammonium chloride, CH3NH3Cl? Assume that the volume of the solutions

are additive and that Kb = 3.70 × 10-4 for methylamine.A) 10.27B) 10.57C) 10.87D) 11.78Answer: BTopic: Section 15.2 The Common-Ion Effect

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22) When equal molar amounts of the following sets of compounds are mixed in water, which will not form a buffer solution?A) NaH2PO4 with Na2HPO4B) NH3 with NH4ClC) CH3CO2H with NaCH3CO2D) HNO3 with NaNO3Answer: DTopic: Section 15.3 Buffer Solutions

23) Which of the following combinations of chemicals could be used to make a buffer solution?A) HCl/NaOHB) HCl/NH3C) HCl/H3PO4D) NaOH/NH3Answer: BTopic: Section 15.3 Buffer Solutions

24) Which statement about buffers is true?A) Buffers have a pH = 7.B) Buffers consist of a strong acid and its conjugate base.C) A buffer does not change pH on addition of a strong acid or strong base.D) Buffers resist change in pH upon addition of small amounts of strong acid or strong base.Answer: DTopic: Section 15.3 Buffer Solutions

25) What is the pH of a buffered system made by dissolving 17.42 g of KH2PO4 and 20.41 g of

K2HPO4 in water to give a volume of 200.0 mL? The Ka2 for dihydrogen phosphate is 6.2 × 10-8 and the equilibrium reaction of interest is

H2PO4-(aq) + H2O(l) ⇌ H3O+(aq) + HPO4-(aq). A) 7.03B) 7.17C) 7.38D) 7.58Answer: BTopic: Section 15.3 Buffer Solutions

26) What is the pH of a buffer system made by dissolving 10.70 grams of NH4Cl and 20.00 mL of 12.0

M NH3 in enough water to make 1.000 L of solution? Kb = 1.8 × 10-5 for NH3.A) 9.18B) 9.26C) 9.34D) 11.03Answer: CTopic: Section 15.3 Buffer Solutions

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27) TRIS {(HOCH2)3CNH2} is one of the most common buffers used in biochemistry. A solution is prepared by adding enough TRIS and 12 M HCl(aq) to give 1.00 L of solution with [TRIS] = 0.30 M and [TRISH+] = 0.60 M. What is the pH of this buffered system if the pKb is 5.92?A) 5.92B) 6.22C) 7.78D) 8.08Answer: CTopic: Section 15.3 Buffer Solutions

28) A buffer solution is prepared by dissolving 0.200 mol of NaH2PO4 and 0.100 mol of NaOH in

enough water to make 1.00 L of solution. What is the pH of the H2PO4-/HPO42- buffer if the

Ka2 = 6.2 × 10-8?

A) 6.91B) 7.21C) 7.51D) 7.71Answer: BTopic: Section 15.3 Buffer Solutions

29) What is the pH of 1 L of 0.30 M TRIS, 0.60 M TRISH+ buffer to which one has added 5.0 mL of 12 M HCl? The Kb for the TRIS/TRISH+ is 1.2 × 10-6.A) 5.92B) 6.36C) 7.36D) 7.64Answer: DTopic: Section 15.3 Buffer Solutions

30) A buffer solution is prepared by dissolving 27.22 g of KH2PO4 and 3.37 g of KOH in enough water

to make 0.100 L of solution. What is the pH of the H2PO4-/HPO42- buffer if the Ka2 = 6.2 × 10-8?

A) 6.84B) 7.00C) 7.21D) 7.84Answer: ATopic: Section 15.3 Buffer Solutions

31) What is the [CH3CO2-]/[CH3CO2H] ratio necessary to make a buffer solution with a pH of 4.44?

Ka = 1.8 × 10-5 for CH3CO2H.A) 0.50:1B) 0.94:1C) 1.1:1D) 2.0:1Answer: ATopic: Section 15.3 Buffer Solutions

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32) What is the pH of a buffer solution made by mixing 50.0 mL of 0.100 M potassium hydrogen phthalate with 13.6 mL of 0.100 M NaOH and diluting the mixture to 100.0 mL with water? The Ka2 for

hydrogen phthalate is 3.1 × 10-6.

A) 3.25B) 5.08C) 5.51D) 5.94Answer: BTopic: Section 15.3 Buffer Solutions

33) What volume of 0.100 M NaOH is needed to make 100.0 mL of a buffer solution with a pH of 6.00 if one starts with 50.0 mL of 0.100 M potassium hydrogen phthalate? The Ka2 for potassium hydrogen

phthalate is 3.1 × 10-6.A) 22.4 mLB) 27.6 mLC) 30.2 mLD) 37.8 mLAnswer: DTopic: Section 15.3 Buffer Solutions

34) What is the magnitude of the change in pH when 0.005 moles of HCl is added to 0.100 L of a buffer solution that is 0.100 M in CH3CO2H and 0.100 M NaCH3CO2? The Ka for acetic acid is1.8 × 10-5.

A) 0.00B) 0.20C) 0.47D) 1.30Answer: CTopic: Section 15.3 Buffer Solutions

35) What is the resulting pH when 0.005 moles of KOH is added to 0.100 L of a buffer solution that is 0.100 M in H2PO4- and 0.100 M HPO42- and the Ka2 = 6.2 × 10-8?

A) 5.21B) 5.61C) 6.73D) 7.69Answer: DTopic: Section 15.3 Buffer Solutions

36) What is the Henderson-Hasselbalch equation for the acidic buffer HA/A-?A) pH = -log[H3O+]B) pH = 14 - pOHC) pH = pKa + log{[A-]/[HA]}

D) pH = pKa - log{[A-]/[HA]}Answer: CTopic: Section 15.4 The Henderson-Hasselbalch Equation

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37) What is not a correct expression for the weak acid HA?A) Ka = [H3O+][A-]/[HA]

B) pKa = pH - log{[A-]/[HA]}C) pKa = logKaD) pKa = 14 - pKbAnswer: CTopic: Section 15.4 The Henderson-Hasselbalch Equation

38) Which is the best acid to use in the preparation of a buffer with pH = 3.3?A) HOI (Ka = 2.0 × 10–11)

B) HNO2 (Ka = 4.5 × 10–4)C) HNO3D) HIO3 ((Ka = 1.7 × 10–1)Answer: BTopic: Section 15.4 The Henderson-Hasselbalch Equation

39) Which is the best acid to use in the preparation of a buffer with pH = 9.3?A) CH3NH2 (Kb = 3.7 × 10–4)

B) NH3 (Kb = 1.8 × 10–5)

C) NH2OH (Kb = 9.1 × 10–9)

D) C6H5NH2 (Kb = 4.3 × 10–10)Answer: BTopic: Section 15.4 The Henderson-Hasselbalch Equation

40) What is the percent dissociation of glycine if the solution has a pH = 8.60 and a pKa = 9.60? A) 50%B) 9%C) 5%D) 1%Answer: BTopic: Section 15.4 The Henderson-Hasselbalch Equation

41) What is the percent dissociation of acetic acid if the solution has a pH = 4.74 and a pKa = 4.74?A) 100%B) 50%C) 10%D) 1%Answer: BTopic: Section 15.4 The Henderson-Hasselbalch Equation

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42) What is the percent dissociation of ascorbic acid if the solution has a pH = 5.50 and a pKa = 4.10? A) 96%B) 10%C) 5%D) 1%Answer: ATopic: Section 15.4 The Henderson-Hasselbalch Equation

43) At what pH is the amino acid glycine with a Ka of 2.51 × 10-10 sixty-six (66%) percent dissociated?A) 9.60B) 9.89C) 10.10D) 10.60Answer: BTopic: Section 15.4 The Henderson-Hasselbalch Equation

44) What volume of 5.00 × 10–3 M HNO3 is needed to titrate 100.00 mL of 5.00 × 10–3 M Ca(OH)2 to the equivalence point?A) 12.5 mLB) 50.0 mLC) 100. mLD) 200. mLAnswer: DTopic: Section 15.6 Strong Acid - Strong Base Titrations

45) What is the pH of a solution made by mixing 30.00 mL of 0.10 M HCl with 40.00 mL of 0.10 M KOH? Assume that the volumes of the solutions are additive.A) 0.85B) 1.85C) 12.15D) 13.15Answer: CTopic: Section 15.6 Strong Acid - Strong Base Titrations

46) Which of the following titrations result in a basic solution at the equivalence point?A) HI titrated with NaCH3CO2B) HOCl titrated with NaOHC) HBr titrated with KOHD) Pb(NO3)2 titrated with NaIAnswer: BTopic: Section 15.7 Weak Acid – Strong Base Titrations

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47) What is the pH at the equivalence point of a weak acid-strong base titration?A) pH < 7B) pH = 7C) pH > 7D) pH = 14.00Answer: CTopic: Section 15.7 Weak Acid – Strong Base Titrations

48) What is the approximate pH at the equivalence point of a weak acid-strong base titration if 25 mL of aqueous formic acid requires 29.80 mL of 0.0567 M NaOH? Ka = 1.8 × 10-4 for formic acid. A) 2.46B) 5.88C) 8.12D) 11.54Answer: CTopic: Section 15.7 Weak Acid – Strong Base Titrations

49) What is the approximate pH at the equivalence point of a weak acid-strong base titration if 25 mL of aqueous hydrofluoric acid requires 30.00 mL of 0.400 M NaOH? Ka = 6.76 × 10-4 for HF.A) 1.74B) 5.75C) 8.25D) 12.26Answer: CTopic: Section 15.7 Weak Acid – Strong Base Titrations

50) The equivalence point pH of the titration of four weak acids is given. Which is the strongest acid?A) 7.24B) 7.86C) 8.12D) 8.43Answer: ATopic: Section 15.7 Weak Acid – Strong Base Titrations

51) Formic acid (HCO2H, Ka = 1.8 × 10-4) is the principal component in the venom of stinging ants. What is the molarity of a formic acid solution if 25.00 mL of the formic acid solution requires 29.80 mL of 0.0567 M NaOH to reach the equivalence point?A) 0.0134 MB) 0.0476 MC) 0.0567 MD) 0.0676 MAnswer: DTopic: Section 15.7 Weak Acid – Strong Base Titrations

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52) What is the pH of the resulting solution if 30.00 mL of 0.10 M acetic acid is added to 10.00 mL of 0.10 M NaOH? Assume that the volumes of the solutions are additive. Ka = 1.8 × 10-5 for CH3CO2H.A) 9.56B) 8.95C) 5.05D) 4.44Answer: DTopic: Section 15.7 Weak Acid – Strong Base Titrations

53) What is the pH of a solution made by mixing 30.00 mL of 0.10 M acetic acid with 30.00 mL of 0.10 M KOH? Assume that the volumes of the solutions are additive. Ka = 1.8 × 10-5 for CH3CO2H.A) 5.28B) 7.00C) 8.72D) 10.02Answer: CTopic: Section 15.7 Weak Acid – Strong Base Titrations

54) What is the pH of a solution made by mixing 30.00 mL of 0.10 M acetic acid with 40.00 mL of 0.10 M KOH? Assume that the volumes of the solutions are additive. Ka = 1.8 × 10-5 for CH3CO2H.A) 8.26B) 9.26C) 11.13D) 12.15Answer: DTopic: Section 15.7 Weak Acid – Strong Base Titrations

55) Which of the following titrations result in an acidic solution at the equivalence point?A) CH3COOH titrated with NaOHB) KF titrated with KOHC) HCl titrated with NaOHD) C5H5N titrated with HClAnswer: DTopic: Section 15.8 Weak Base – Strong Acid Titrations

56) Sodium hypochlorite, NaOCl, is the active ingredient in household bleach. What is the concentration of hypochlorite ion if 20.00 mL of bleach requires 28.30 mL of 0.500 M HCl to reach the equivalence point?A) 0.208 MB) 0.353 MC) 0.708 MD) 1.21 MAnswer: CTopic: Section 15.8 Weak Base – Strong Acid Titrations

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57) What is the pH at the equivalence point of a weak base-strong acid titration if 20.00 mL of NaOCl requires 28.30 mL of 0.50 M HCl? Ka = 3.0 × 10-8 for HOCl.A) 0.30B) 3.18C) 3.76D) 4.03Answer: DTopic: Section 15.8 Weak Base – Strong Acid Titrations

58) The equivalence point pH of the titration of four weak bases is given. Which is the strongest base?A) 4.21B) 5.67C) 6.33D) 7.58Answer: DTopic: Section 15.8 Weak Base – Strong Acid Titrations

59) What is the pH of the resulting solution if 25 mL of 0.432 M methylamine, CH3NH2, is added to

15 mL of 0.234 M HCl? Assume that the volumes of the solutions are additive. Ka = 2.70 × 10-11 for

CH3NH3+.A) 3.11B) 3.74C) 10.26D) 10.89Answer: DTopic: Section 15.8 Weak Base – Strong Acid Titrations

60) Sulfurous acid, H2SO3 has acid dissociation constants Ka1 = 1.5 × 10–2 and Ka2 = 6.3 × 10–8. What is the pH after 10.00 mL of 0.1000 M NaOH is added to 10.00 mL of 0.1000 M H2SO3?A) 1.82B) 3.60C) 4.25D) 7.20Answer: CTopic: Section 15.9 Polyprotic Acid – Strong Base Titrations

61) Oxalic acid, H2C2O4 has acid dissociation constants Ka1 = 5.9 × 10–2 and Ka2 = 6.4 × 10–5. What is the pH after 20.00 mL of 0.0500 M NaOH is added to 5.00 mL of 0.2000 M H2C2O4?A) 1.23B) 2.10C) 2.80D) 4.19Answer: CTopic: Section 15.9 Polyprotic Acid – Strong Base Titrations

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62) The dissociation equilibrium constants for the protonated form of alanine (a diprotic amino acid, H2X+) are Ka1 = 4.6 × 10-3 and Ka2 = 2.0 × 10-10. What is the pH of 50.00 mL of a 0.0500 M solution

of alanine after 25.00 mL of 0.100 M NaOH has been added?A) 2.34B) 4.85C) 5.59D) 6.72Answer: CTopic: Section 15.9 Polyprotic Acid – Strong Base Titrations

63) The dissociation equilibrium constants for the protonated form of alanine (a diprotic amino acid, H2X+) are Ka1 = 4.6 × 10-3 and Ka2 = 2.0 × 10-10. What is the pH of 50.00 mL of a 0.050 M solution

of alanine after 37.50 mL of 0.100 M NaOH has been added?A) 4.85B) 6.02C) 7.39D) 9.70Answer: DTopic: Section 15.9 Polyprotic Acid – Strong Base Titrations

64) The dissociation equilibrium constants for the protonated form of alanine (a diprotic amino acid H2X+) are Ka1 = 4.6 × 10-3 and Ka2 = 2.0 × 10-10. What is the pH of 50.00 mL of a 0.100 M solution

of alanine after 100.00 mL of 0.100 M NaOH has been added?A) 9.70B) 10.69C) 11.11D) 12.70Answer: CTopic: Section 15.9 Polyprotic Acid – Strong Base Titrations

65) The balanced equation for the solubility equilibrium of Fe(OH)2 is shown below. What is the equilibrium constant expression for the Ksp of Fe(OH)2?

Fe(OH)2(s) ⇌ Fe2+(aq) + 2 OH-(aq)

A) Ksp = {[Fe2+][OH-]2}/{[Fe(OH)2][H2O]}

B) Ksp = {[Fe2+][OH-]2}/[Fe(OH)2]

C) Ksp = [Fe2+][OH-]2

D) Ksp = 1/{[Fe2+][OH-]2}Answer: CTopic: Section 15.10 Solubility Equilibria

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66) What is the equilibrium constant expression for the Ksp of Ca3(PO4)2?

A) Ksp = [Ca2+]3[PO43-]2

B) Ksp = {[Ca2+]3[PO43-]2}/[Ca3PO4]

C) Ksp = {[Ca2+]3[PO43-]2}/{[Ca3PO4][H2O]}

D) Ksp = 1/{[Ca2+]3[PO43-]2}Answer: ATopic: Section 15.10 Solubility Equilibria

67) What is the silver ion concentration for a saturated solution of Ag2CO3 if the Ksp for Ag2CO3 is

8.4 × 10-12?A) 2.90 × 10-6 MB) 2.03 × 10-4 MC) 2.56 × 10-4 MD) 4.06 × 10-4 MAnswer: CTopic: Section 15.11 Measuring Ksp and Calculating Solubility from Ksp

68) What is the chromium ion concentration for a saturated solution of Cr(OH)3 if the Ksp for Cr(OH)3

is 6.7 × 10-31?A) 8.19 × 10-16 MB) 1.26 × 10-8 MC) 2.17 × 10-8 MD) 3.76 × 10-8 MAnswer: BTopic: Section 15.11 Measuring Ksp and Calculating Solubility from Ksp

69) What is the most soluble salt of the following set?A) Ba(OH)2 with Ksp = 5.0 × 10-3

B) Ca(OH)2 with Ksp = 4.7 × 10-6

C) Cd(OH)2 with Ksp = 5.3 × 10-15

D) Fe(OH)2 with Ksp = 2.5 × 10-37

Answer: ATopic: Section 15.11 Measuring Ksp and Calculating Solubility from Ksp

70) What is the most soluble salt of the following set?A) AgCN with Ksp = 6.0 × 10-17

B) Al(OH)3 with Ksp = 1.9 × 10-33

C) Fe(OH)3 with Ksp = 2.6 × 10-39

D) Sn(OH)2 with Ksp = 1.6 × 10-19

Answer: DTopic: Section 15.11 Measuring Ksp and Calculating Solubility from Ksp

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71) Calculate the Ksp for silver sulfate if the solubility of Ag2SO4 in pure water is 4.5 g/L.

A) 3.0 × 10-6 B) 1.2 × 10-5

C) 2.1 × 10-4 D) 4.2 × 10-4Answer: BTopic: Section 15.11 Measuring Ksp and Calculating Solubility from Ksp

72) Calculate the solubility (in g/L) of silver carbonate in water at 25°C if the Ksp for Ag2CO3 is

8.4 × 10-12.A) 8.0 × 10-4 g/LB) 3.5 × 10-2 g/LC) 4.4 × 10-2 g/LD) 5.6 × 10-2 g/LAnswer: BTopic: Section 15.11 Measuring Ksp and Calculating Solubility from Ksp

73) What is the molar solubility of CaF2 in 0.10 M NaF solution at 25°C? The Ksp for CaF2 is

A) 8.5 × 10-10 MB) 3.4 × 10-10 MC) 3.4 × 10-9 MD) 2.0 × 10-4 MAnswer: CTopic: Section 15.12 Factors That Affect Solubility

74) What is the molar solubility of Mg(OH)2 in a basic solution with a pH of 12.00? Ksp for Mg(OH)2

is 5.6 × 10-12.A) 5.6 × 10-10 MB) 5.6 × 10-8 MC) 2.4 × 10-6 MD) 1.1 × 10-4 MAnswer: BTopic: Section 15.12 Factors That Affect Solubility

75) Calculate the molar solubility of thallium(I) chloride in 0.30 M NaCl at 25°C. Ksp for TlCl is

1.7 × 10-4.A) 5.1 × 10-5 MB) 5.7 × 10-4 MC) 7.1 × 10-3 MD) 1.3 × 10-2 MAnswer: BTopic: Section 15.12 Factors That Affect Solubility

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76) What is the molar solubility of lead(II) chromate in 0.10 M HNO3 if the Ksp for PbCrO4 is

2.8 × 10-13? and the Ka2 for H2CrO4 is 3.0 × 10-7? Note that H2CrO4 is considered to be a strong acid.

A) 9.2 × 10-11 MB) 2.9 × 10-10 MC) 9.3 × 10-7 MD) 3.1 × 10-4 MAnswer: DTopic: Section 15.12 Factors That Affect Solubility

77) In which of the following solutions would solid PbCl2 be expected to be the least soluble at 25°C?A) 0.1 M HClB) 0.1 M NaClC) 0.1 M CaCl2D) 0.1 M KNO3Answer: CTopic: Section 15.12 Factors That Affect Solubility

78) What is the molar solubility of AgCl in 0.10 M NH3? Ksp for AgCl is 1.8 × 10-10 and the Kf for

Ag(NH3)2+ is 1.7 × 107.

A) 1.3 × 10-5 MB) 5.0 × 10-3 MC) 5.5 × 10-3 MD) 5.5 × 10-2 MAnswer: BTopic: Section 15.12 Factors That Affect Solubility

79) What is the molar solubility of AgCl in 1.0 M K2S2O3 if the complex ion Ag(S2O3)23- forms? The

Ksp for AgCl is 1.8 × 10-10 and the Kf for Ag(S2O3)23- is 2.9 × 1013.A) 0.50 MB) 1.0 MC) 1.5 MD) 2.0 MAnswer: ATopic: Section 15.12 Factors That Affect Solubility

80) What is the molar solubility of AgCl in 0.10 M NaCN if the colorless complex ion Ag(CN)2- forms?

Ksp for AgCl is 1.8 × 10-10 and Kf for Ag(CN)2- is A) 0.050 MB) 0.10 MC) 0.20 MD) 0.40 MAnswer: ATopic: Section 15.12 Factors That Affect Solubility

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81) Which of the following metal hydroxides are amphoteric?A) Al(OH)3, Zn(OH)2, Cr(OH)3, Sn(OH)2B) Cu(OH)2, Mn(OH)2, Fe(OH)2, Fe(OH)3C) Be(OH)2, Ca(OH)2, Ba(OH)2, Sr(OH)3D) LiOH, NaOH, KOH, RbOHAnswer: ATopic: Section 15.12 Factors That Affect Solubility

82) Which of the following reactions are not consistent with the concept of acid base amphoterism?A) Al(OH)3(s) + OH-(aq) → Al(OH)4-(aq)

B) Al(OH)3(s) + 3 H3O+(aq) → Al3+(aq) + 6 H2O(l)

C) H2O(l) + H2O(l) ⇌ H3O+(aq) + OH-(aq)

D) Al(OH)3(s) ⇌ Al3+(aq) + 3 OH-(aq)Answer: DTopic: Section 15.12 Factors That Affect Solubility

83) Precipitation of an ionic compound will occur upon mixing of desired reagents if the initial ion product is ________.A) greater than the KspB) equal to the pKspC) equal to the KspD) less than the KspAnswer: ATopic: Section 15.13 Precipitation of Ionic Compounds

84) Potassium chromate is slowly added to a solution containing 0.20 M AgNO3 and 0.20 M Ba(NO3)2.

Describe what happens if the Ksp for Ag2CrO4 is 1.1 × 10-12 and the Ksp of BaCrO4 is 1.2 × 10-10.A) The BaCrO4 precipitates first out of solution.B) The Ag2CrO4 precipitates first out of solution and then BaCrO4 precipitates.C) Both BaCrO4 and Ag2CrO4 precipitate simultaneously out of solution.D) Neither BaCrO4 nor Ag2CrO4 precipitates out of solution.Answer: BTopic: Section 15.13 Precipitation of Ionic Compounds

85) 0.10 M potassium chromate is slowly added to a solution containing 0.20 M AgNO3 and 0.20 M

Ba(NO3)2. What is the Ag+ concentration when BaCrO4 just starts to precipitate? Ksp for Ag2CrO4

and BaCrO4 are 1.1 × 10-12 and 1.2 × 10-10, respectively.

A) 6.5 × 10-5 MB) 1.3 × 10-4 MC) 3.2 × 10-4 MD) 4.3 × 10-2 MAnswer: DTopic: Section 15.13 Precipitation of Ionic Compounds

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86) Which metal sulfides can be precipitated from a solution that is 0.01 M in Mn2+, Zn2+, Pb2+ and Cu2+ and 0.10 M in H2S at a pH of 1.0?

A) MnSB) CuSC) PbS, CuSD) ZnS, PbS, CuSAnswer: DTopic: Section 15.13 Precipitation of Ionic Compounds

87) Which metal sulfides can be precipitated from a solution that is 0.01 M in Mn2+, Zn2+, Pb2+ and Cu2+ and 0.10 M in H2S at a pH of 0.50?

A) MnSB) CuSC) PbS, CuSD) ZnS, PbS, CuSAnswer: CTopic: Section 15.13 Precipitation of Ionic Compounds

88) Which metal ions can be precipitated out of solution as chlorides?A) Ag+, Hg2+, Co2+ B) Cu2+, Cd2+, Bi3+

C) Ag+, Hg22+, Pb2+

D) Na+, K+, Mg2+Answer: CTopic: Section 15.13 Precipitation of Ionic Compounds

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89) A solution may contain the following ions Ag+, Cu2+, Cd2+, Mn2+, Ni2+ and Na+. A white precipitate formed when 0.10 M NaCl was added and after this was removed the solution was treated with H2S gas under acidic conditions and no precipitate formed. When the solution was made basic and again treated with H2S gas a dark colored precipitate formed. If no further tests were made then what conclusions can you draw?A) possible ions present Ag+, Mn2+, Ni2+

B) possible ions present Ag+, Mn2+, Ni2+, Na+

C) possible ions present Ag+, Cu2+, Cd2+

D) possible ions present Ag+, Cu2+, Cd2+, Na+Answer: BTopic: Section 15.13 Precipitation of Ionic Compounds

90) A solution may contain the following ions Ag+, Cu2+, Mn2+, Ca2+, and Na+. No precipitate formed when 0.10 M NaCl was added but a dark colored precipitate formed when H2S was added to an acidic portion of the solution. After the removal of the solid the solution was made basic and more H2S was added and a dark precipitate again formed. Treatment of the filtrate with (NH4)2CO3 resulted in a white precipitate. If no further tests were made then what conclusions can you draw?A) possible ions present Cu2+, Mn2+, Na+

B) possible ions present Cu2+, Mn2+, Ca2+

C) possible ions present Cu2+, Mn2+, Ca2+, Na+

D) possible ions present Ag+, Cu2+, Mn2+, Ca2+, Na+Answer: CTopic: Section 15.13 Precipitation of Ionic Compounds

91) Which set of ions precipitate as sulfides?A) Ag+, Pb2+, Mn2+

B) Pb2+, Fe2+, Ca2+

C) Co2+, Ba2+, K+

D) NH4+, Na+, K+

Answer: ATopic: Section 15.13 Precipitation of Ionic Compounds

92) Which pair of ions can be separated by the addition of chloride ion?A) Ag+ and Co2+

B) Cu2+ and Bi3+

C) Pb2+ and Hg22+

D) Ca2+ and Ba2+Answer: ATopic: Section 15.14 Separation of Ions by Selective Precipitation

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93) Which pair of ions can be separated by the addition of sulfide ion?A) Ag+ and Cu2+

B) Cu2+ and Bi3+

C) Pb2+ and Ca2+

D) Ca2+ and Ba2+Answer: CTopic: Section 15.14 Separation of Ions by Selective Precipitation

The following pictures represent solutions that contain a weak acid HA and/or its potassium salt KA. Unshaded spheres represent H atoms and shaded spheres represent A- ions. (K+, H3O+, OH-, and solvent H2O molecules have been omitted for clarity.)

94) Which solution has the highest pH?A) (1)B) (2)C) (3)D) (4)Answer: DTopic: Conceptual Problems

95) Which solution has the lowest pH?A) (1)B) (2)C) (3)D) (4)Answer: BTopic: Conceptual Problems

96) Which solution has the largest percent dissociation of HA?A) (1)B) (2)C) (3)D) (4)Answer: DTopic: Conceptual Problems

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97) Which of the solutions are buffer solutions?A) (1) and (2)B) (1) and (3)C) (2) and (3)D) (2) and (4)Answer: BTopic: Conceptual Problems

98) Which solution has the greatest buffer capacity?A) (1)B) (2)C) (3)D) (4)Answer: CTopic: Conceptual Problems

99) For which solution(s) is pH = pKa?A) only solution (1)B) only solution (2)C) only solution (3)D) solutions (1) and (3)Answer: DTopic: Conceptual Problems

The following pictures represent solutions that contain a weak acid HA (pKa = 5.0) and its potassium

salt KA. Unshaded spheres represent H atoms and shaded spheres represent A- ions. (K+, H3O+, OH-, and solvent H2O molecules have been omitted for clarity.)

100) Which solution has the highest pH?A) (1)B) (2)C) (3)D) (4)Answer: BTopic: Conceptual Problems

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101) Which solution has the lowest pH?A) (1)B) (2)C) (3)D) (4)Answer: CTopic: Conceptual Problems

102) Which solution has the largest percent dissociation of HA?A) (1)B) (2)C) (3)D) (4)Answer: BTopic: Conceptual Problems

103) Which of these solutions are buffers?A) (1) and (2)B) (1) and (3)C) (1), (2) and (3)D) All are buffer solutions.Answer: DTopic: Conceptual Problems

104) Which solution has the greatest buffer capacity?A) (1)B) (2)C) (3)D) (4)Answer: DTopic: Conceptual Problems

105) For which of these solutions is pH = pKa?A) All have pH = pKa. B) (1), (2) and (3)C) (1) and (4)D) (2) and (3)Answer: CTopic: Conceptual Problems

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The following pictures represent solutions that contain a weak acid HA (pKa = 5.0) and its potassium salt KA. Unshaded spheres represent H atoms, black spheres represent oxygen atoms, and shaded spheres represent A- ions. (K+, H3O+ initially present, OH- initially present and solvent water molecules have been omitted for clarity.)

106) Which picture represents the equilibrium state of the solution after addition of one H3O+ ion to the solution shown in picture (1)?A) (2)B) (3)C) (4)D) (5)Answer: CTopic: Conceptual Problems

107) Which picture represents the equilibrium state of the solution after addition of one OH- ion to the solution shown in picture (1)?A) (2)B) (3)C) (4)D) (5)Answer: BTopic: Conceptual Problems

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The following pictures represent solutions at various points in the titration of a weak acid HA with aqueous KOH. Unshaded spheres represent H atoms, black spheres represent oxygen atoms, and shaded spheres represent A- ions. (K+, H3O+ initially present, OH- initially present and solvent water molecules have been omitted for clarity).

108) Which picture represents the solution before the addition of any KOH?A) (1)B) (2)C) (3)D) (4)Answer: DTopic: Conceptual Problems

109) Which picture represents the solution before the equivalence point?A) (1)B) (2)C) (3)D) (4)Answer: BTopic: Conceptual Problems

110) Which picture represents the solution at the equivalence point?A) (1)B) (2)C) (3)D) (4)Answer: ATopic: Conceptual Problems

111) Which picture represents the solution after the equivalence point?A) (1)B) (2)C) (3)D) (4)Answer: CTopic: Conceptual Problems

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The following pictures represent solutions at various stages in the titration of a weak diprotic acid H2A with aqueous KOH. Unshaded spheres represent H atoms, black spheres represent oxygen atoms, and shaded spheres represent A2- ions. (K+, H3O+ initially present, OH- initially present and solvent water molecules have been omitted for clarity).

112) Which picture represents the system halfway to the first equivalence point?A) (1)B) (2)C) (3)D) (4)Answer: BTopic: Conceptual Problems

113) Which picture represents the system at the first equivalence point?A) (1)B) (2)C) (3)D) (4)Answer: DTopic: Conceptual Problems

114) Which picture represents the system halfway between the first and second equivalence points?A) (1)B) (2)C) (3)D) (4)Answer: ATopic: Conceptual Problems

115) Which picture represents the system beyond the second equivalence point?A) (1)B) (2)C) (3)D) (4)Answer: CTopic: Conceptual Problems

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116) Which picture represents the system with the highest pH?A) (1)B) (2)C) (3)D) (4)Answer: CTopic: Conceptual Problems

117) Which picture represents the system with the lowest pH?A) (1)B) (2)C) (3)D) (4)Answer: BTopic: Conceptual Problems

Use the graphs below to answer the following questions.

118) What is the characteristic pH-titrant curve for the titration of a strong acid by a strong base?A) AB) BC) CD) DAnswer: BTopic: Conceptual Problems

119) What is the characteristic pH-titrant curve for the titration of a strong base by a strong acid?A) AB) BC) CD) DAnswer: CTopic: Conceptual Problems

120) What is the characteristic pH-titration curve for the titration of a weak acid by a strong base?A) AB) BC) CD) DAnswer: ATopic: Conceptual Problems

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The following plot shows two titration curves, each representing the titration of 50.00 mL of 0.100 M acid with 0.100 M NaOH.

121) Which point a-d represents the equivalence point for the titration of a strong acid?A) point aB) point bC) point cD) point dAnswer: DTopic: Conceptual Problems

122) Which point a-d represents the equivalence point for the titration of a weak acid?A) point aB) point bC) point cD) point dAnswer: CTopic: Conceptual Problems

123) At which point a-d is the pKa of the acid equal to the pH?A) point aB) point bC) point cD) point dAnswer: ATopic: Conceptual Problems

124) Which points a-d represent the half-equivalence point and the equivalence point, respectively, for the titration of a weak acid?A) points a and bB) points a and c C) points b and dD) points c and dAnswer: BTopic: Conceptual Problems

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125) Which point a-d represents a buffer region?A) point aB) point bC) point cD) point dAnswer: ATopic: Conceptual Problems

The following plot shows a titration curve for the titration of 1.00 L of 1.00 M diprotic acid H2A with NaOH.

126) A buffer region is indicated by which point(s) a-d?A) point aB) points a and cC) point bD) points b and dAnswer: BTopic: Conceptual Problems

127) Which point a-d represents the HX-/X2- buffer region?A) point aB) point bC) point cD) point dAnswer: CTopic: Conceptual Problems

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128) Which point a-d represents the H2X/HX- buffer region?A) point aB) point bC) point cD) point dAnswer: ATopic: Conceptual Problems

129) Which point a-d represents the first equivalence point?A) point aB) point bC) point cD) point dAnswer: BTopic: Conceptual Problems

130) Which point a-d represents the second equivalence point?A) point aB) point bC) point cD) point dAnswer: DTopic: Conceptual Problems

131) Which point a-d represents pKa1?A) point aB) point bC) point cD) point dAnswer: ATopic: Conceptual Problems

132) Which point a-d represents pKa2?A) point aB) point bC) point cD) point dAnswer: CTopic: Conceptual Problems

133) What is the pH at the first equivalence point?A) pH = pKa1B) pH = 14 - pKa1C) pH = (pKa1 + pKa2)/2D) pH = pKa1 + pKa2Answer: CTopic: Conceptual Problems

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134) The following plot shows a titration curve for the titration of 1.00 L of 1.00 M diprotic acid H2A+ with NaOH. Which point a-d represents the isoelectric point?

A) point aB) point bC) point cD) point dAnswer: BTopic: Conceptual Problems

The following pictures represent solutions of CuS, which may also contain ions other than Cu2+ and S2-

which are not shown. Gray spheres represent Cu2+ ions and dotted spheres represent S2- ions.

135) If solution (1) is a saturated solution of CuS, which of solutions (2)-(4) are unsaturated?A) only (2)B) only (3)C) only (4)D) (3) and (4)Answer: DTopic: Conceptual Problems

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136) If solution (1) is a saturated solution of CuS, which of solutions (2)-(4) are saturated?A) (2)B) (3)C) (4)D) None of theseAnswer: DTopic: Conceptual Problems

137) If solution (1) is a saturated solution of CuS, which of solutions (2)-(4) are supersaturated?A) (2)B) (3)C) (4)D) None of theseAnswer: ATopic: Conceptual Problems

The following pictures represent solutions of AgCl, which may also contain ions other than Ag+ and Cl-

which are not shown. Gray spheres represent Ag+ ions and dotted spheres represent Cl- ions.

138) If solution (1) is a saturated solution of AgCl, which of solutions (1)-(4) represents the solution after a small amount of HCl is added and equilibrium is restored?A) (1)B) (2)C) (3)D) (4)Answer: DTopic: Conceptual Problems

139) If solution (1) is a saturated solution of AgCl, which of solutions (1)-(4) represents the solution after a small amount of HNO3 is added and equilibrium is restored?A) (1)B) (2)C) (3)D) (4)Answer: ATopic: Conceptual Problems

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140) If solution (1) is a saturated solution of AgCl, which of solutions (1)-(4) represents the solution after a small amount of AgNO3 is added and equilibrium is restored?A) (1)B) (2)C) (3)D) (4)Answer: BTopic: Conceptual Problems

141) If solution (1) is a saturated solution of AgCl, which of solutions (1)-(4) represents the solution after a small amount of NH3 is added and equilibrium is restored?A) (1)B) (2)C) (3)D) (4)Answer: DTopic: Conceptual Problems

The following pictures represent solutions of CaCO3, which may also contain ions other than Ca2+ and

CO32- which are not shown. Gray spheres represent Ca2+ ions and unshaded spheres represent CO32- ions.

142) If solution (1) is a saturated solution of CaCO3, which of solutions (1)-(4) represents the solution after a small amount of NaOH is added and equilibrium is restored?A) (1)B) (2)C) (3)D) (4)Answer: DTopic: Conceptual Problems

143) If solution (1) is a saturated solution of CaCO3, which of solutions (1)-(4) represents the solution after a small amount of HNO3 is added and equilibrium is restored?A) (1)B) (2)C) (3)D) (4)Answer: BTopic: Conceptual Problems

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144) If solution (1) is a saturated solution of CaCO3, which of solutions (1)-(4) represents the solution after a small amount of Ca(NO3)2 is added and equilibrium is restored?A) (1)B) (2)C) (3)D) (4)Answer: BTopic: Conceptual Problems

145) If solution (1) is a saturated solution of CaCO3, which of solutions (1)-(4) represents the solution after a small amount of K2CO3 is added and equilibrium is restored?A) (1)B) (2)C) (3)D) (4)Answer: DTopic: Conceptual Problems

15.2 Algorithmic Questions

1) What is the hydronium ion concentration in a solution prepared by mixing 50.00 mL of 0.10 M HCN with 50.00 mL of 0.030 M NaCN? Assume that the volumes of the solutions are additive and that Ka = 4.9 × 10-10 for HCN.

A) 1.5 × 10- 10 MB) 4.9 × 10-10 MC) 1.6 × 10- 9 MD) 7.0 × 10-6 MAnswer: CTopic: Section 15.2 The Common-Ion Effect

2) What is the pH of a solution prepared by mixing 25.00 mL of 0.10 M CH3CO2H with 25.00 mL of

0.0 10 M CH3CO2Na? Assume that the volume of the solutions are additive and that Ka = 1.8 × 10-5 for CH3CO2H. A) 2.87B) 3.74C) 4.7 5D) 5. 74Answer: BTopic: Section 15.2 The Common-Ion Effect

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3) What is the pH of a solution prepared by mixing 50.00 mL of 0.10 M NH3 with 5.00 mL of 0.10 M

NH4Cl? Assume that the volume of the solutions are additive and that Kb = 1.8 × 10-5 for NH3. A) 8. 25 B) 10.26 C) 10.25D) 11.13Answer: CTopic: Section 15.2 The Common-Ion Effect

4) What is the pH of a solution prepared by mixing 50.00 mL of 0.10 M methylamine, CH3NH2, with 20.00 mL of 0.10 M methylammonium chloride, CH3NH3Cl? Assume that the volume of the solutions

are additive and that Kb = 3.70 × 10-4 for methylamine. A) 10.17B) 10.57C) 10.97D) 11.78Answer: CTopic: Section 15.2 The Common-Ion Effect

5) What is the pH of a buffer system prepared by dissolving 10.70 grams of NH4Cl and 25.00 mL of

12 M NH3 in enough water to make 1.000 L of solution? Kb = 1.80 × 10-5 for NH3. A) 9.08B) 9.26C) 9. 43D) 11. 32Answer: CTopic: Section 15.3 Buffer Solutions

6) What is the [CH3CO2-]/[CH3CO2H] ratio necessary to make a buffer solution with a pH of 4.34?

Ka = 1.8 × 10-5 for CH3CO2H. A) 0. 39:1 B) 0. 91:1C) 1. 09:1D) 2.5:1Answer: ATopic: Section 15.3 Buffer Solutions

7) What volume of 5.00 × 10–3 M HNO3 is needed to titrate 80.00 mL of 5.00 × 10–3 M Ca(OH)2 to the equivalence point? A) 10.0 mLB) 40.0 mLC) 80.0 mLD) 160. mLAnswer: DTopic: Section 15.6 Strong Acid - Strong Base Titrations

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8) What is the pH of a solution made by mixing 25.00 mL of 0. 100 M HCl with 40.00 mL of 0.100 M KOH? Assume that the volumes of the solutions are additive.A) 0.64B) 1.64C) 12.36D) 13.36Answer: CTopic: Section 15.6 Strong Acid - Strong Base Titrations

9) What is the approximate pH at the equivalence point of a weak acid-strong base titration if 25 mL of

aqueous formic acid requires 29.80 mL of 0.3567 M NaOH? Ka =1.8 × 10-4 for formic acid.A) 2. 06B) 5. 48C) 8. 52D) 11.94Answer: CTopic: Section 15.7 Weak Acid – Strong Base Titrations

10) What is the approximate pH at the equivalence point of a weak acid-strong base titration if 25 mL of aqueous hydrofluoric acid requires 30.00 mL of 0.400 M NaOH? Ka = 6.76 × 10-4 for HF. A) 1.74B) 5.75C) 8.25D) 12.26Answer: CTopic: Section 15.7 Weak Acid – Strong Base Titrations

11) Formic acid (HCO2H, Ka = 1.8 × 10-4) is the principal component in the venom of stinging ants. What is the molarity of a formic acid solution if 25.00 mL of the formic acid solution requires 29.80 mL of 0.0567 M NaOH to reach the equivalence point?A) 0.0134 MB) 0.0 476 MC) 0.0567 MD) 0. 0676 MAnswer: DTopic: Section 15.7 Weak Acid – Strong Base Titrations

12) What is the pH of the resulting solution if 25.00 mL of 0.10 M acetic acid is added to 10.00 mL of

0.10 M NaOH? Assume that the volumes of the solutions are additive. Ka = 1.8 × 10-5 for CH3CO2H A) 9. 43B) 9.08C) 4.92D) 4. 57Answer: DTopic: Section 15.7 Weak Acid – Strong Base Titrations

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13) What is the pH of a solution made by mixing 10.00 mL of 0.10 M acetic acid with 10.00 mL of 0.10 M KOH? Assume that the volumes of the solutions are additive. Ka =1.8 × 10-5 for CH3CO2H. A) 5.28B) 7.00C) 8.72D) 10.02Answer: CTopic: Section 15.7 Weak Acid – Strong Base Titrations

14) What is the pH of a solution made by mixing 30.00 mL of 0.10 M acetic acid with 50.00 mL of 0. 100 M KOH? Assume that the volumes of the solutions are additive. Ka = 1.8 × 10-5 for CH3CO2H.A) 8.26B) 9.26C) 11.13D) 12. 40Answer: DTopic: Section 15.7 Weak Acid – Strong Base Titrations

15) Sodium hypochlorite, NaOCl, is the active ingredient in household bleach. What is the concentration of hypochlorite ion if 20.00 mL of bleach requires 32.00 mL of 0.500 M HCl to reach the equivalence point?A) 0. 300 MB) 0. 312 MC) 0. 800 MD) 1. 30 MAnswer: CTopic: Section 15.8 Weak Base – Strong Acid Titrations

16) What is the pH at the equivalence point of a weak base-strong acid titration if 20.00 mL of NaOCl requires 28.30 mL of 0. 50 M HCl? Ka = 3.0 × 10-8 for HOCl.A) 0.30B) 3. 18C) 3.76D) 4. 03Answer: DTopic: Section 15.8 Weak Base – Strong Acid Titrations

17) What is the pH of the resulting solution if 45 mL of 0.432 M methylamine, CH3NH2, is added to

15 mL of 0.234 M HCl? Assume that the volumes of the solutions are additive. Ka = 2.70 × 10-11 for

CH3NH3+. A) 2.77B) 4.09C) 9.91D) 11.23Answer: DTopic: Section 15.8 Weak Base – Strong Acid Titrations

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18) Calculate the Ksp for silver sulfite if the solubility of Ag2SO3 in pure water is 4.6 × 10-3 g/L.

A) 3.8 × 10-15

B) 1.5 × 10-14

C) 2.4 × 10-10

D) 4.8 × 10-10Answer: BTopic: Section 15.11 Measuring Ksp and Calculating Solubility from Ksp

19) Calculate the solubility (in g/L) of silver chromate in water at 25°C if the Ksp for Ag2CrO4 is

1.1 × 10-12.A) 3.5 × 10-4 g/LB) 6.5 × 10-5 g/LC) 2.7 × 10-2 g/LD) 3.4 × 10-2 g/LAnswer: BTopic: Section 15.11 Measuring Ksp and Calculating Solubility from Ksp

20) What is the molar solubility of Mg(OH)2 in a basic solution with a pH of 12.50? Ksp for Mg(OH)2

is 5.61 × 10-12.A) 1.8 × 10- 10 MB) 5.6 × 10- 9 MC) 2.4 × 10-6 MD) 1.1 × 10-4 MAnswer: BTopic: Section 15.12 Factors That Affect Solubility

21) Calculate the molar solubility of thallium(I) chloride in 0. 40 M NaCl at 25°C. Ksp for TlCl is

1.7 × 10-4.A) 6.8 × 10-5 MB) 4.2 × 10- 4 MC) 8.2 × 10-3 MD) 1.3 × 10-2 MAnswer: BTopic: Section 15.12 Factors That Affect Solubility

22) In which of the following solutions would solid PbBr2 be expected to be the least soluble at 25°C?A) 0.1 M H BrB) 0.1 M NaBrC) 0.1 M CaBr2D) 0.1 M K NO3Answer: CTopic: Section 15.12 Factors That Affect Solubility

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23) What is the molar solubility of AgCl in 0. 20 M NH3? Ksp for AgCl is 1.8 × 10-10 and Kf for

Ag(NH3)2+ is 1.7 × 107.

A) 1.3 × 10-5 MB) 1.0 × 10- 2 MC) 1.1 × 10- 2 MD) 5.5 × 10-2 MAnswer: BTopic: Section 15.12 Factors That Affect Solubility

24) What is the molar solubility of AgCl in 0. 10 M NaCN if the colorless complex ion Ag(CN)2-

forms? Ksp for AgCl is 1.8 × 10-10 and Kf for Ag(CN)2- is 1.0 × 1021. A) 0. 050 MB) 0. 10 MC) 0.20 MD) 0.40 MAnswer: ATopic: Section 15.12 Factors That Affect Solubility

25) 0.10 M potassium chromate is slowly added to a solution containing 0. 50 M AgNO3 and 0. 50 M

Ba(NO3)2. What is the Ag+ concentration when BaCrO4 just starts to precipitate? The Ksp for

Ag2CrO4 and BaCrO4 are 1.1 × 10-12 and 1.2 × 10-10, respectively.

A) 6.5 × 10-5 MB) 1.3 × 10-4 MC) 3.2 × 10-4 MD) 6.8 × 10-2 MAnswer: DTopic: Section 15.13 Precipitation of Ionic Compounds

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15.3 Short Answer Questions

1) The balanced net ionic equation for the neutralization reaction involving equal molar amounts of HNO3 and KOH is ________.

Answer: H3O+(aq) + OH–(aq) ⇌ 2 H2O(l)Topic: Section 15.1 Neutralization Reactions

2) The balanced net ionic equation for the neutralization reaction involving equal molar amounts ofHCl and CH3CH2NH2 is ________.

Answer: H3O+(aq) + CH3CH2NH2 ⇌ CH3CH2NH3+ + H2O(l)Topic: Section 15.1 Neutralization Reactions

3) What is the equation relating the equilibrium constant Kn for the neutralization of a weak acid with a weak base to the Ka of the acid, the Kb of the base and Kw?

Answer: Kn =

Topic: Section 15.1 Neutralization Reactions

4) The neutralization constant Kn for the neutralization of penicillin V (C16H18N2O5S) and

erythromycin (C37H67NO13) is 1.3 × 106. The acid dissociation constant Ka for penicillin V is

2.0 × 10-3. What is the base dissociation constant Kb for erythromycin?

Answer: 6.5 × 10-6Topic: Section 15.1 Neutralization Reactions

5) The solution formed upon adding 50.00 mL of 0.10 M NH4Cl to 50.00 mL of 0.10 M NH3 will have a pH that is ________ the pH of the original NH3 solution.Answer: lower thanTopic: Section 15.2 The Common-Ion Effect

6) The pH of a solution of HIO3 (Ka = 1.7 × 10-1) and KIO3 is 1.00. What is the molarity of KIO3 if the molarity of HIO3 is 0.025 M? Answer: 0.043 MTopic: Section 15.2 The Common-Ion Effect

7) The pH of a solution of ethylamine, C2H5NH2 (Kb = 6.4 × 10-4) and ethylammium bromide, C2H5NH3Br is 11.00. What is the molarity of C2H5NH3Br if the molarity of C2H5NH2 is 0.025 M?Answer: 0.016 MTopic: Section 15.2 The Common-Ion Effect

8) A buffer prepared by mixing 50.00 mL of 0.10 M HF with 50.00 mL of 0.10 M NaF will have a pH that is ________ 7.0.Answer: less thanTopic: Section 15.4 The Henderson-Hasselbalch Equation

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9) A buffer prepared by mixing equal moles of an acid having Ka = 4.5 × 10–4 and a salt of its conjugate base has a pH = ________.Answer: 3.35Topic: Section 15.4 The Henderson-Hasselbalch Equation

10) The pH of a 0.150 M formic acid/0.250 M sodium formate buffer = ________? The Ka of formic

acid is 1.8 × 10–4.Answer: 3.56Topic: Section 15.4 The Henderson-Hasselbalch Equation

11) Addition of 0.0125 mol KOH to 150 mL of a 0.150 M formic acid/0.100 M sodium formate buffer results in a pH = ________? The Ka of formic acid is 1.8 × 10–4.Answer: 4.43Topic: Section 15.4 The Henderson-Hasselbalch Equation

12) Addition of 0.0125 mol HCl to 150 mL of a 0.150 M formic acid/0.100 M sodium formate buffer results in a pH = ________? The Ka of formic acid is 1.8 × 10–4.Answer: 3.89Topic: Section 15.4 The Henderson-Hasselbalch Equation

13) What is the Ka of the amino acid glycine if it is 75.0% dissociated at pH = 10.08?

Answer: 2.5 × 10-10Topic: Section 15.4 The Henderson-Hasselbalch Equation

14) What is the Ka of the amino acid glutamine if it is 33.0% dissociated at pH = 8.82?

Answer: 7.5 × 10-10Topic: Section 15.4 The Henderson-Hasselbalch Equation

15) The addition of ________ mL of 0.1500 M NaOH is required to titrate 25.00 mL of 0.2250 M HCl to the equivalence point, which occurs at a pH of ________.Answer: 37.50, 7.00Topic: Section 15.6 Strong Acid - Strong Base Titrations

16) What is the pH of the solution formed when 50 mL of 0.250 M NaOH is added to 50 mL of 0.120 M HCl? Answer: 12.81Topic: Section 15.6 Strong Acid - Strong Base Titrations

17) What is the pH of the solution formed when 25 mL of 0.173 M NaOH is added to 35 mL of 0.342 M HCl? Answer: 0.89Topic: Section 15.6 Strong Acid - Strong Base Titrations

18) The half equivalence point in the titration of 0.100 M HCO2H (Ka = 1.8 × 10–4) with 0.250 M NaOH occurs at pH = ________.Answer: 3.74Topic: Section 15.7 Weak Acid – Strong Base Titrations

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19) The half equivalence point in the titration of 0.100 M CH3NH2 (Kb = 3.7 × 10–4) with 0.250 M HCl occurs at pH = ________.Answer: 10.57Topic: Section 15.8 Weak Base – Strong Acid Titrations

20) Selenous acid, H2SeO3 has acid dissociation constants Ka1 = 3.5 × 10–2 and Ka2 = 5 × 10–8. When 25.00 mL of 0.100 M selenous acid is titrated with 0.200 M NaOH the first equivalence point occurs at pH = ________.Answer: 4.2Topic: Section 15.9 Polyprotic Acid – Strong Base Titrations

21) At 25°C calcium fluoride has a solubility product constant Ksp = 3.5 × 10–11. The solubility of CaF2 at this temperature is ________ mol/L.

Answer: 2.1 × 10–4Topic: Section 15.11 Measuring Ksp and Calculating Solubility from Ksp

22) Silver oxalate, Ag2C2O4, has a molar solubility = 1.1 × 10-4 mol/L. Ag2C2O4 has a solubility product Ksp = ________.

Answer: 5.4 × 10-12Topic: Section 15.11 Measuring Ksp and Calculating Solubility from Ksp

23) The artist’s pigment cadmium yellow, CdS, has a water solubility of 0.13 g/L. The solubility product of CdS, Ksp = ________.

Answer: 8.1 × 10-7Topic: Section 15.11 Measuring Ksp and Calculating Solubility from Ksp

24) State whether the solubility of Cu(OH)2 will increase or decrease upon the addition of aqueous solutions of a) HCl, b) NaOH, c) NH3.Answer: a) increase, b) decrease, c) increaseTopic: Section 15.12 Factors That Affect Solubility

25) CaF2 has Ksp = 3.5 × 10-11. If 25 mL of 8.0 × 10-4 M Ca(NO3)2 is mixed with 75 mL of

4.0 × 10-4 M KF, a precipitate of CaF2 ________ (will, will not) form. Answer: will notTopic: Section 15.13 Precipitation of Ionic Compounds

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