Chapter 17 - Solubility and Complex-Ion Equilibria Cation C and anion A form an ionic compound for which Ksp = s2, where s is the molar solubility of the ionic compound Which of Figures I–III represent(s) possible results of the mixing of an aqueous solution containing cation C with an aqueous solution containing anion A? A) B) C) D) E) only I only III both I and III both I and II only II ANS: OBJ: TOP: MSC: D PTS: DIF: moderate REF: 17.1 Write solubility product expressions (Example 17.1) solubility | solubility equilibria KEY: solubility product constant general chemistry Cation C and anion A form an ionic compound for which Ksp = 4s3, where s is the molar solubility of the ionic compound Which of Figures I–III represent(s) possible results of the mixing of an aqueous solution containing cation C with an aqueous solution containing anion A? A) B) C) D) E) only III only II both I and II only I both I and III ANS: C PTS: DIF: moderate OBJ: Write solubility product expressions (Example 17.1) REF: 17.1 TOP: solubility | solubility equilibria MSC: general chemistry KEY: solubility product constant Which of the following particulate views is/are consistent with a heterogeneous equilibrium? I A) B) C) D) E) II III I only II only III only II and III I, II, and III ANS: C PTS: DIF: easy OBJ: Write solubility product expressions (Example 17.1) TOP: solubility | solubility equilibria REF: 17.1 What is the solubility product expression for Al(OH)3? A) Ksp = [Al3+][3OH–] B) Ksp = 3[Al3+][OH–]3 C) Ksp = [Al3+][OH–]3 D) Ksp = [Al3+][3OH–]3 E) Ksp = [Al3+][OH–] ANS: OBJ: TOP: MSC: C PTS: DIF: easy REF: 17.1 Write solubility product expressions (Example 17.1) solubility | solubility equilibria KEY: solubility product constant general chemistry What is the solubility product expression for Th(IO3)4? A) Ksp = [Th4+][4IO3–]4 B) Ksp = [Th4+][IO3–] C) Ksp = [Th][IO3]4 D) Ksp = [Th4+][IO3–]4 E) Ksp = [Th4+][IO3–] ANS: OBJ: TOP: MSC: D PTS: DIF: easy REF: 17.1 Write solubility product expressions (Example 17.1) solubility | solubility equilibria KEY: solubility product constant general chemistry What is the solubility product expression for Zn3(PO4)2? A) Ksp = [Zn32+][(PO43–)2] B) C) D) E) Ksp = [3Zn2+]3[2PO43–]2 Ksp = [Zn2+][2PO43–] Ksp = [Zn3+]2[PO42–]3 Ksp = [Zn2+]3[PO43–]2 ANS: OBJ: TOP: MSC: E PTS: DIF: easy REF: 17.1 Write solubility product expressions (Example 17.1) solubility | solubility equilibria KEY: solubility product constant general chemistry What is the solubility product expression for mercury(I) iodide, Hg2I2? A) Ksp = [Hg22+][2I–]2 B) Ksp = [Hg22+][I–]2 C) Ksp = [Hg22+][2I– ] D) Ksp = [Hg2][I2] E) Ksp = [Hg+]2[I–]2 ANS: OBJ: TOP: MSC: B PTS: DIF: moderate REF: 17.1 Write solubility product expressions (Example 17.1) solubility | solubility equilibria KEY: solubility product constant general chemistry What is the solubility product expression for La2(CO3)3? A) Ksp = [2La3+]2[3CO32–]3 B) Ksp = [La2+]2[CO32–]3 C) Ksp = [2La3+]2[CO32–]3 D) Ksp = [2La3+][3CO32–] E) Ksp = [La3+]2[CO32–]3 ANS: OBJ: TOP: MSC: E PTS: DIF: easy REF: 17.1 Write solubility product expressions (Example 17.1) solubility | solubility equilibria KEY: solubility product constant general chemistry What is the solubility product expression for Pb3(PO4)4? A) Ksp = [Pb3+]4[PO44–]3 B) Ksp = [3Pb3+][4PO43–] C) Ksp = [3Pb3+]3[4PO43–]4 D) Ksp = [Pb2+]3[PO43–]2 E) Ksp = [Pb4+]3[PO43–]4 ANS: OBJ: TOP: MSC: E PTS: DIF: easy REF: 17.1 Write solubility product expressions (Example 17.1) solubility | solubility equilibria KEY: solubility product constant general chemistry 10 What is the solubility product expression for Sn(IO3)2? A) Ksp = [Sn2+][IO3–]2 B) Ksp = [Sn4+][2IO32–]2 C) Ksp = [Sn2+][2IO3–] D) Ksp = [Sn4+][IO32–]2 E) Ksp = [Sn2+][2IO3–]2 ANS: OBJ: TOP: MSC: A PTS: DIF: easy REF: 17.1 Write solubility product expressions (Example 17.1) solubility | solubility equilibria KEY: solubility product constant general chemistry 11 Figures I–IV represent ionic compounds formed upon the mixing of an aqueous solution containing cation C with an aqueous solution containing anion A Identify the figure(s) that represent(s) products for which Ksp = s2, where s is the molar solubility of the ionic compound A) B) C) D) E) only I only II only IV only III both I and II ANS: D PTS: OBJ: Define molar solubility KEY: solubility product constant DIF: moderate REF: 17.1 TOP: solubility | solubility equilibria MSC: general chemistry 12 Figures I–IV represent ionic compounds formed upon the mixing of an aqueous solution containing cation C with an aqueous solution containing anion A Identify the figure(s) that represent(s) products for which Ksp = 4s3, where s is the molar solubility of the ionic compound A) B) C) D) E) both I and II only II only IV only I only III ANS: A PTS: OBJ: Define molar solubility KEY: solubility product constant DIF: moderate REF: 17.1 TOP: solubility | solubility equilibria MSC: general chemistry 13 Figures I–IV represent ionic compounds formed upon the mixing of an aqueous solution containing cation C with an aqueous solution containing anion A Identify the figure(s) that represent(s) products for which Ksp = 108s5, where s is the molar solubility of the ionic compound A) B) C) D) E) only II both I and II only IV only III only I ANS: C PTS: OBJ: Define molar solubility KEY: solubility product constant DIF: moderate REF: 17.1 TOP: solubility | solubility equilibria MSC: general chemistry 14 What is the relationship between molar solubility (s) and Ksp for calcium fluoride? A) B) C) D) E) ANS: A PTS: OBJ: Define molar solubility KEY: solubility product constant DIF: easy REF: 17.1 TOP: solubility | solubility equilibria MSC: general chemistry 15 What is the correct mathematical expression for finding the molar solubility (s) of Sn(OH)2? A) 2s3 = Ksp B) 4s3 = Ksp C) 108s5 = Ksp D) 2s2 = Ksp E) 8s3 = Ksp ANS: B PTS: OBJ: Define molar solubility KEY: solubility product constant DIF: easy REF: 17.1 TOP: solubility | solubility equilibria MSC: general chemistry 16 The concentration of calcium carbonate in a saturated aqueous solution of the salt at 25°C is 6.71  10 5 M What is the Ksp of this sparingly soluble salt? A) 4.50  10 9 B) 1.21  10 12 C) 5.47  10 16 D) 8.19  10 3 E) 4.06  10 2 ANS: A PTS: DIF: easy REF: 17.1 OBJ: Calculate Ksp from the solubility (simple example) (Example 17.2) TOP: solubility | solubility equilibria 17 The solubility of strontium carbonate in water at 25°C is 4.50  10 this sparingly soluble salt? A) 9.30  10 10 B) 1.13  10 13 C) 2.34  10 17 D) 5.52  10 3 E) 3.12  10 2 3 g/L What is the Ksp of ANS: A PTS: DIF: easy REF: 17.1 OBJ: Calculate Ksp from the solubility (simple example) (Example 17.2) TOP: solubility | solubility equilibria 18 After mixing an excess PbCl2 with a fixed amount of water, it is found that the equilibrium concentration of Pb2+ is 1.6  10–2 M What is Ksp for PbCl2? A) 4.0  10–6 B) 1.6  10–5 C) 2.5  10–4 D) 4.8  10–2 E) 1.0  10–6 ANS: OBJ: TOP: MSC: B PTS: DIF: moderate REF: 17.1 Calculate Ksp from the solubility (more complicated example).(Example 17.3) solubility | solubility equilibria KEY: solubility product constant general chemistry 19 The solubility of lead(II) sulfate is 4.0  10–2 g/L What is the solubility product constant for lead(II) sulfate? A) 1.7  10–8 B) 1.3  10–4 C) 1.6  10–3 D) 4.6  10–15 E) 8.9  10–12 ANS: OBJ: TOP: MSC: A PTS: DIF: moderate REF: 17.1 Calculate Ksp from the solubility (more complicated example).(Example 17.3) solubility | solubility equilibria KEY: solubility product constant general chemistry 20 The solubility of silver(I) carbonate is 3.6  10–2 g/L What is the solubility product constant for silver(I) carbonate? A) 4.4  10–15 B) 8.9  10 12 C) 1.7  10–8 D) 1.3  10–4 E) 1.3  10–3 ANS: OBJ: TOP: MSC: B PTS: DIF: moderate REF: 17.1 Calculate Ksp from the solubility (more complicated example).(Example 17.3) solubility | solubility equilibria KEY: solubility product constant general chemistry 21 The hydroxide ion concentration of a saturated solution of Fe(OH)2 is 1.16  10 is the solubility product constant for Fe(OH)2? A) 7.80  10 16 B) 6.24  10 15 C) 1.56  10 15 D) 3.41  10 3 E) 2.26  10 2 5 M What ANS: A PTS: DIF: moderate REF: 17.1 OBJ: Calculate Ksp from the solubility (more complicated example).(Example 17.3) TOP: solubility | solubility equilibria NOT: REVISED 22 The silver-ion concentration in a saturated solution of silver(I) chromate is 1.3  10–4 M What is Ksp for silver(I) chromate? A) 2.9  10–16 B) 4.2  10–9 C) 8.8  10–12 D) 1.1  10 12 E) 1.7  10–8 ANS: D PTS: DIF: difficult REF: 17.1 OBJ: Calculate Ksp from the solubility (more complicated example).(Example 17.3) TOP: solubility | solubility equilibria MSC: general chemistry KEY: solubility product constant 23 Which of the following salts has the highest molar solubility in water? A) SrCO3 (Ksp = 9.3  10–10) B) BaSO4 (Ksp = 1.1  10–10 ) C) PbS (Ksp = 2.5  10–27) D) BaCrO4 (Ksp = 1.2  10–10) E) AgCl (Ksp = 1.8  10–10 ) ANS: OBJ: TOP: KEY: A PTS: DIF: easy Calculate the solubility from Ksp (Example 17.4) solubility | solubility equilibria solubility product constant | relative solubilities REF: 17.1 MSC: general chemistry 24 Which of the following salts has the lowest molar solubility? A) SrCO3 (Ksp = 9.3  10–10) B) MnS (Ksp = 2.5  10–10) C) BaF2 (Ksp = 1.0  10–6) D) BaSO4 (Ksp = 1.1  10–10) E) AgCl (Ksp = 1.8  10–10) ANS: OBJ: TOP: KEY: D PTS: DIF: easy Calculate the solubility from Ksp (Example 17.4) solubility | solubility equilibria solubility product constant | relative solubilities REF: 17.1 MSC: general chemistry 25 Rank the following salts in order of increasing molar solubility Salt BaSO4 AgCl BaCO3 CdS PbSO4 A) B) C) D) E) Ksp 1.1  10–10 1.8  10–10 9.1  10–9  10–27 1.8  10–8 CdS < AgCl < BaSO4 < BaCO3 < PbSO4 CdS < AgCl < BaCO3 < BaSO4 < PbSO4 CdS < BaSO4 < AgCl < BaCO3 < PbSO4 PbSO4 < BaCO3 < AgCl < BaSO4 < CdS PbSO4 < BaCO3 < BaSO4 < AgCl < CdS ANS: OBJ: TOP: KEY: C PTS: DIF: easy Calculate the solubility from Ksp (Example 17.4) solubility | solubility equilibria solubility product constant | relative solubilities REF: 17.1 MSC: general chemistry 26 A saturated solution of which of the following salts will have the lowest molar concentration of chromate ion? A) B) C) D) E) BaCrO4 (Ksp = 2.1  10-10) CuCrO4 (Ksp = 3.6  10-6) Ag2CrO4 (Ksp = 1.2  10-12) Hg2CrO4 (Ksp = 2.0  10-9) Tl2CrO4 (Ksp = 9.8  10-13) ANS: A PTS: DIF: easy OBJ: Calculate the solubility from Ksp (Example 17.4) TOP: solubility | solubility equilibria REF: 17.1 27 A saturated solution of which of the following salts will have the greatest molar concentration of silver ion? A) B) C) D) E) Ag2S (Ksp =  10-51) AgCl (Ksp = 1.8  10-10) Ag2CrO4 (Ksp = 1.2  10-12) Ag2CO3 (Ksp = 8.1  10-12) Ag4Fe(CN)6 (Ksp = 8.5  10-45) ANS: D PTS: DIF: moderate OBJ: Calculate the solubility from Ksp (Example 17.4) TOP: solubility | solubility equilibria REF: 17.1 28 What is the solubility (in g/L) of aluminum hydroxide at 25°C? The solubility product constant for aluminum hydroxide is 4.6  10–33 at 25°C A) 3.6  10–31 g/L B) 8.2  10–10 g/L C) 2.8  10–7 g/L D) 5.3  10–15 g/L E) 1.8  10–31 g/L ANS: OBJ: TOP: MSC: C PTS: DIF: easy REF: 17.1 Calculate the solubility from Ksp (Example 17.4) solubility | solubility equilibria KEY: solubility product constant general chemistry 29 What is the solubility (in g/L) of silver(I) bromide at 25°C? The solubility product constant for silver(I) bromide is 5.0  10–13 at 25°C A) 9.4  10–3 g/L B) 9.4  10–11 g/L C) 1.3  10–4 g/L D) 4.7  10–11 g/L E) 7.9  10–2 g/L ANS: OBJ: TOP: MSC: C PTS: DIF: easy REF: 17.1 Calculate the solubility from Ksp (Example 17.4) solubility | solubility equilibria KEY: solubility product constant general chemistry 30 Rank the following metal sulfides in order of increasing molar solubility in water Salt CoS CuS FeS HgS MnS A) B) C) D) E) Ksp  10–21  10–36  10–18 1.6  10–52 2.5  10–10 MnS < FeS < CoS < CuS < HgS FeS < HgS < CoS < CuS < MnS HgS < CuS < CoS < FeS < MnS CuS < CoS < FeS < MnS < HgS CoS < CuS < FeS < HgS < MnS ANS: OBJ: TOP: KEY: C PTS: DIF: easy Calculate the solubility from Ksp (Example 17.4) solubility | solubility equilibria solubility product constant | relative solubilities REF: 17.1 MSC: general chemistry 31 What is the molar solubility of silver(I) bromide at 25°C? The solubility product constant for silver(I) bromide is 5.0  10–13 at 25°C A) 7.1  10–7 M B) 2.5  10–13 M C) 4.2  10–4 M D) 5.0  10–5 M E) 5.0  10–13 M ANS: OBJ: TOP: MSC: A PTS: DIF: easy REF: 17.1 Calculate the solubility from Ksp (Example 17.4) solubility | solubility equilibria KEY: solubility product constant general chemistry 32 What is the molar solubility of calcium sulfate at 25°C? The solubility product constant for calcium sulfate is 2.4  10–5 at 25°C A) 2.4  10–5 M B) 3.5  10–2 M C) 1.2  10–5 M D) 1.8  10–2 M E) 4.9  10–3 M ANS: OBJ: TOP: MSC: E PTS: DIF: easy REF: 17.1 Calculate the solubility from Ksp (Example 17.4) solubility | solubility equilibria KEY: solubility product constant general chemistry B) C) D) E) Silver(I) nitrate will precipitate Sodium iodide will precipitate Silver(I) iodide will precipitate No precipitate will form ANS: D PTS: DIF: easy REF: 17.3 OBJ: Predict whether precipitation will occur (given solution volumes and concentrations) (Example 17.7) TOP: solubility | solubility equilibria KEY: precipitation calculations | criterion for precipitation MSC: general chemistry 70 If 315 mL of  10–4 M Ca(NO3)2 is mixed with 315 mL of  10–4 M NaF, what will occur? For CaF2, Ksp = 3.4  10–11 A) No precipitate will form B) Sodium nitrate will precipitate C) Calcium nitrate will precipitate D) Calcium fluoride will precipitate E) Sodium fluoride will precipitate ANS: A PTS: DIF: moderate REF: 17.3 OBJ: Predict whether precipitation will occur (given solution volumes and concentrations) (Example 17.7) TOP: solubility | solubility equilibria KEY: precipitation calculations | criterion for precipitation MSC: general chemistry 71 If 270 mL of  10–8 M Al(NO3)3 is mixed with 270 mL of  10–8 M NaOH, what will occur? For Al(OH)3, Ksp = 4.6  10–33 A) Aluminum hydroxide will precipitate B) Sodium hydroxide will precipitate C) Aluminum nitrate will precipitate D) Sodium nitrate will precipitate E) No precipitate will form ANS: E PTS: DIF: moderate REF: 17.3 OBJ: Predict whether precipitation will occur (given solution volumes and concentrations) (Example 17.7) TOP: solubility | solubility equilibria KEY: precipitation calculations | criterion for precipitation MSC: general chemistry 72 What is the minimum mass of Na2CO3 that must be added to 24.6 mL of a 9.5  10– M AgNO3 solution in order for precipitation to occur? For Ag2CO3, Ksp = 8.6  10–12 A) 2.5  10–3 g B) 3.1  10–4 g C) 1.2  10–3 g D) 2.4  10–8 g E) 2.5  10–5 g ANS: E PTS: DIF: moderate REF: 17.3 OBJ: Predict whether precipitation will occur (given solution volumes and concentrations) (Example 17.7) TOP: solubility | solubility equilibria KEY: precipitation calculations | criterion for precipitation MSC: general chemistry 73 What is the maximum volume of 4.9  10–5 M K2CrO4 that, added to 17.0 mL of a solution that is 8.6  10–5 M Ba(NO3)2 and 5.4  10–6 M Pb(NO3)2, will precipitate PbCrO4 but not BaCrO4? For PbCrO4, Ksp = 1.8  10–14, and for BaCrO4, Ksp = 1.2  10–10 A) 17 mL B) 0.51 mL C) 0.48 mL D) 0.0012 mL E) 7.7 mL ANS: B PTS: DIF: difficult REF: 17.3 OBJ: Predict whether precipitation will occur (given solution volumes and concentrations) (Example 17.7) TOP: solubility | solubility equilibria KEY: precipitation calculations | fractional precipitation MSC: general chemistry 74 A solution is 0.010 M in each of Pb(NO3)2, Mn(NO3)2, and Zn(NO3)2 Solid NaOH is added until the pH of the solution is 8.50 Which of the following statements is true? Salt Pb(OH)2 Mn(OH)2 Zn(OH)2 A) B) C) D) E) Ksp 1.4  10–20 2.0  10–13 2.1  10–16 Only Mn(OH)2 will precipitate All three hydroxides will precipitate Only Pb(OH)2 will precipitate No precipitate will form Only Zn(OH)2 and Pb(OH)2 will precipitate ANS: OBJ: TOP: KEY: E PTS: DIF: moderate REF: 17.3 Explain how two ions can be separated using fractional precipitation solubility | solubility equilibria precipitation calculations | fractional precipitation MSC: general chemistry 75 What is the maximum concentration of carbonate ions that will precipitate BaCO3 but not 3 MgCO3 from a solution that is 2.7  10 M each in Mg2+ and Ba2+? For MgCO3, Ksp = 1.0  10–5 and for BaCO3, Ksp = 2.6  10–9 A) 3.7  10 3 M B) 9.6  10 7 M C) 2.7  10 8 M D) 7.0  10 12 M E) 2.6  10–14 M ANS: OBJ: TOP: KEY: A PTS: DIF: moderate REF: 17.3 Explain how two ions can be separated using fractional precipitation solubility | solubility equilibria precipitation calculations | fractional precipitation MSC: general chemistry 76 Which of the following solutions should be added to a solution containing both copper(II) ions and silver(I) ions in order to precipitate only one of the ions? A) HCl(aq) B) H2S(aq) C) HNO3(aq) D) H2S(aq) + HCl(aq) E) H2S(aq) + HNO3(aq) ANS: OBJ: TOP: KEY: A PTS: DIF: easy REF: 17.3 Explain how two ions can be separated using fractional precipitation solubility | solubility equilibria precipitation calculations | fractional precipitation MSC: general chemistry 77 For which pair of cations would the addition of dilute hydrobromic acid precipitate one but not the other? A) Ag+ and Ca2+ B) Hg22+ and Ag+ C) Ba2+ and Na+ D) Ca2+ and Ba2+ E) Pb2+ and Ag+ ANS: OBJ: TOP: KEY: A PTS: DIF: easy REF: 17.3 Explain how two ions can be separated using fractional precipitation solubility | solubility equilibria precipitation calculations | fractional precipitation MSC: general chemistry 78 Sodium chloride is added slowly to a solution that is 0.010 M in Cu+, Ag+, and Au+ The Ksp values for the chloride salts are 1.9  10–7, 1.6  10–10, and 2.0  10–13, respectively Which compound will precipitate first? A) AuCl(s) B) All will precipitate at the same time C) It cannot be determined D) AgCl(s) E) CuCl(s) ANS: OBJ: TOP: KEY: A PTS: DIF: moderate REF: 17.3 Explain how two ions can be separated using fractional precipitation solubility | solubility equilibria precipitation calculations | fractional precipitation MSC: general chemistry 79 Solid KCN is added to a solution composed of 0.10 M Ag+ and 0.10 M Zn2+ just until a precipitate forms What is the composition of this initial precipitate? AgCN Ksp = 2.2  1016 and Zn(CN)2 Ksp =  10-16 A) The precipitate is pure AgCN(s) B) The precipitateis pure Zn(CN)2(s) C) The precipitate is a mixture of AgCN(s) and Zn(CN)2(s) D) The precipitate is a mixture of KCN(s) and AgCN(s) E) The precipitate is a mixture of KCN(s) and Zn(CN)2(s) ANS: A PTS: DIF: moderate REF: 17.3 OBJ: Explain how two ions can be separated using fractional precipitation TOP: solubility | solubility equilibria 80 Silver nitrate (AgNO3) is slowly added to a solution containing 0.100 M Br and 0.050 M FeCN64 until a precipitate just forms What is the molar concentration of Ag+ just as the precipitate forms? AgBr Ksp = 5.0  10-13 and Ag4FeCN6 Ksp = 8.5  10-45 A) 2.0  10-11 M Ag+ B) 5.0  10-12 M Ag+ C) 1.0  10-11 M Ag+ D) 3.3  10-12 M Ag+ E) 1.7  10-43 M Ag+ ANS: B PTS: DIF: moderate REF: 17.3 OBJ: Explain how two ions can be separated using fractional precipitation TOP: solubility | solubility equilibria 81 A solution contains 0.018 mol each of I–, Br–, and Cl– When the solution is mixed with 200 mL of 0.24 M AgNO3, how much AgCl(s) precipitates out? Ksp AgI = 1.5  10–16 Ksp AgBr = 5.0  10–13 Ksp AgCl = 1.6  10–10 A) B) C) D) E) 5.0 g 3.3 g 2.6 g 0.0 g 1.7 g ANS: OBJ: TOP: KEY: E PTS: DIF: difficult REF: 17.3 Explain how two ions can be separated using fractional precipitation solubility | solubility equilibria precipitation calculations | fractional precipitation MSC: general chemistry 82 The best explanation for the dissolution of ZnS in dilute HCl is that A) the zinc ion is amphoteric B) the sulfide ion concentration is decreased by the formation of H2S C) the solubility product of ZnCl2 is less than that of ZnS D) the zinc ion concentration is decreased by the formation of a chloro complex E) the sulfide ion concentration is decreased by oxidation to sulfur ANS: OBJ: TOP: KEY: B PTS: DIF: easy REF: 17.4 Explain the qualitative effect of pH on solubility of a slightly soluble salt solubility | solubility equilibria effect of pH on solubility | qualitative effect of pH MSC: general chemistry 83 You have two salts, AgX and AgY, with very similar Ksp values You know that Ka for HX is much greater than Ka for HY Which statement will be true? A) AgX and AgY are less soluble in acidic solution than in pure water B) AgX is more soluble in acidic solution C) AgX and AgY are equally soluble in acidic solution D) AgY is more soluble in acidic solution E) none of these ANS: OBJ: TOP: KEY: D PTS: DIF: moderate REF: 17.4 Explain the qualitative effect of pH on solubility of a slightly soluble salt solubility | solubility equilibria effect of pH on solubility | qualitative effect of pH MSC: general chemistry 84 For which of the following salts would the addition of nitric acid increase its solubility? A) AgI B) AgNO3 C) AgCl D) Ag2SO4 E) AgBr ANS: OBJ: TOP: KEY: D PTS: DIF: easy REF: 17.4 Determine the qualitative effect of pH on solubility (Example 17.8) solubility | solubility equilibria effect of pH on solubility | qualitative effect of pH MSC: general chemistry 85 Which of the following substances will increase the molar solubility of nickel(II) phosphate in a saturated solution? A) AgCl B) HNO3 C) KOH D) AlPO4 E) Na3PO4 ANS: OBJ: TOP: KEY: B PTS: DIF: easy REF: 17.4 Determine the qualitative effect of pH on solubility (Example 17.8) solubility | solubility equilibria effect of pH on solubility | qualitative effect of pH MSC: general chemistry 86 In which of the following solutions would CaC2O4 have the highest molar solubility? A) 0.01 M Na2C2O4 B) 0.01 M NaCl C) 0.01 M HCl D) 0.01 M Ca(NO3)2 E) 0.01 M NaHC2O4 ANS: OBJ: TOP: KEY: C PTS: DIF: easy REF: 17.4 Determine the qualitative effect of pH on solubility (Example 17.8) solubility | solubility equilibria effect of pH on solubility | qualitative effect of pH MSC: general chemistry 87 The figure below represents the results of adding a strong acid to a saturated solution of an ionic compound Which of the following could be the ionic compound? A) B) C) D) E) AgClO4 AgF AgI AgCl AgBr ANS: OBJ: TOP: KEY: B PTS: DIF: easy REF: 17.4 Determine the qualitative effect of pH on solubility (Example 17.8) solubility | solubility equilibria effect of pH on solubility | qualitative effect of pH MSC: general chemistry 88 What is the best way to ensure complete precipitation of SnS from a saturated H2S solution? A) Add a strong acid B) Add a weak acid C) Add a strong base D) Add a weak base E) Add more H2S ANS: C PTS: DIF: moderate REF: 17.4 OBJ: Explain the basis for the sulfide scheme to separate a mixture of metal ions TOP: solubility | applications of solubility equilibria MSC: general chemistry 89 Suppose hydrogen sulfide is added to a solution that is 0.10 M in Cu2+, Pb2+, and Ni2+ such that the concentration of H2S is 0.10 M When the pH of the solution is adjusted to 1.00, a precipitate forms What is the composition of the precipitate? 2H3O+(aq) + S2–(aq); Kc = 1.1  10–20 H2S(aq) + 2H2O(l) Salt CuS PbS NiS A) B) C) D) E) Ksp 6.0  10–36 2.5  10–27 3.0  10–19 CuS only PbS and NiS CuS and PbS NiS only CuS, PbS, and NiS ANS: C PTS: DIF: difficult REF: 17.4 OBJ: Explain the basis for the sulfide scheme to separate a mixture of metal ions TOP: solubility | solubility equilibria KEY: effect of pH on solubility MSC: general chemistry 90 Suppose hydrogen sulfide is added to a solution that is 0.0010 M in Fe2+, Cd2+, Co2+, and Mn2+ such that the concentration of H2S is 0.10 M When the pH of the solution is adjusted to 3, a precipitate forms What is the composition of the precipitate? H2S(aq) + 2H2O(l) Salt FeS CdS CoS MnS A) B) C) D) E) 2H3O+(aq) + S2–(aq); Kc = 1.1  10–20 Ksp 6.0  10–18 8.0  10–27 4.0  10–21 2.5  10–10 CdS only CdS, CoS, FeS, and MnS CdS, CoS, and FeS CdS and FeS CdS and CoS ANS: OBJ: TOP: MSC: E PTS: DIF: difficult REF: 17.4 Explain the basis for the sulfide scheme to separate a mixture of metal ions solubility | solubility equilibria KEY: effect of pH on solubility general chemistry 91 What is the value of the dissociation constant, Kd, for the complex ion Cd(NH3)42+? For Cd(NH3)42+, Kf = 1.0  107 A) 1.0  10–7 B) 2.5  106 C) 1.0  107 D) 5.6  101 E) 1.0  10–7 ANS: OBJ: TOP: MSC: E PTS: DIF: easy REF: 17.5 Define formation constant or stability constant, Kf, and dissociation constant, Kd solubility | complex ion equilibria KEY: complex ion formation general chemistry 92 Which of the following is not likely to form a complex ion with Al3+? A) NH4+ B) NH3 C) OH D) H2O E) CH3NH2 ANS: A PTS: DIF: easy REF: 17.5 OBJ: Define formation constant or stability constant, Kf, and dissociation constant, Kd TOP: solubility | complex ion equilibria 93 Which of the following statements concerning amphoteric hydroxides is/are correct? A) B) C) D) E) The amphoteric hydroxide of aluminum(III) is commercially used to separate aluminum(III) oxide from impurities in the aluminum ore bauxite Amphoteric hydroxides form soluble complex ions at high pH’s The amphoteric hydroxide, Zn(OH)2, can be precipitated by increasing the pH of a solution containing Zn2+(aq) or lowering the pH of a solution containing Zn(OH)42 only only only and 1, 2, and ANS: E PTS: DIF: easy REF: 17.5 OBJ: Define formation constant or stability constant, Kf, and dissociation constant, Kd TOP: solubility | complex ion equilibria 94 Calculate the molar concentration of uncomplexed Zn2+(aq) in a solution that contains 0.22 mol of Zn(NH3)42+ per liter and 0.3109 M NH3 at equilibrium Kf for Zn(NH3)42+ is 2.9  10 A) 8.1  10 9 M B) 2.4  10 10 M C) 1.2  10 M D) 7.8  10 10 M E) 6.8  10 10 M ANS: A PTS: DIF: easy REF: 17.5 OBJ: Calculate the concentration of a metal ion in equilibrium with a complex ion (Example 17.9) TOP: solubility | complex ion equilibria 95 Cyanide ion forms very stable complex ions with a variety of metal ions What is the molar equilibrium concentration of uncomplexed Cu2+(aq) in a solution that initially contains 16 1.3 mol of Cu(CN)2 per liter of solution Kf for Cu(CN)2 is 2.8  10 A) 2.3  10 6 M B) 3.6  10 6 M C) 4.4  10 M D) 3.4  10 9 M E) 1.2  10 17 M ANS: A PTS: DIF: easy REF: 17.5 OBJ: Calculate the concentration of a metal ion in equilibrium with a complex ion (Example 17.9) TOP: solubility | complex ion equilibria 96 What is the molar equilibrium concentration of uncomplexed Ag+(aq) in a solution composed of 1.1 mol Ag(CN)2 dissolved in 1.00 L of 0.47 M NaCN Kf for Ag(CN)2 is 4.5  10 10 A) 1.1  10 10 M B) 5.2  10 11 M C) 9.0  10 M D) 2.4  10 10 M E) 1.1  10 5 M ANS: A PTS: DIF: easy REF: 17.5 OBJ: Calculate the concentration of a metal ion in equilibrium with a complex ion (Example 17.9) TOP: solubility | complex ion equilibria 97 An aqueous solution of Ag(CN)2is made by combining 0.0100 moles AgNO3 with 1.00 mole NaCN and diluting to 1.000 L What is the molar concentration of Ag+ in the solution? Ag+(aq) + 2CN–(aq) Ag(CN)2–(aq); Kf = 5.6  1018 -21 A) 1.9  10 M B) C) D) E) 5.3  1020 M 5.8  1016 M 1.7  10-17 M 0.010 M ANS: A PTS: DIF: moderate REF: 17.5 OBJ: Calculate the concentration of a metal ion in equilibrium with a complex ion (Example 17.9) TOP: solubility | complex ion equilibria KEY: complex ion formation | equilibrium calculations with Kf MSC: general chemistry 98 Suppose sodium hydroxide is added to a 0.0016 M solution of zinc nitrate such that the pH of the solution is 13.42 What is the equilibrium concentration of Zn2+? Zn2+(aq) + 4OH–(aq) Zn(OH)42–(aq); Kf = 2.8  1015 –18 A) 2.2  10 M B) C) D) E) 1.6  10–3 M 6.6  10–2 M 1.2  10–16 M 2.2  10–18 M ANS: D PTS: DIF: moderate REF: 17.5 OBJ: Calculate the concentration of a metal ion in equilibrium with a complex ion (Example 17.9) TOP: solubility | complex ion equilibria KEY: complex ion formation | equilibrium calculations with Kf MSC: general chemistry 99 What is the concentration of Cd2+ in a 0.010 M Cd(NO3)2 solution that is also 1.0 M NH3? For Cd(NH3)42+, Kf = 1.0  107 A) B) C) D) E) 3.2  10–5 M 1.0  10–9 M 1.2  10–9 M 3.2  10–4 M 1.0  10–2 M ANS: C PTS: DIF: difficult REF: 17.5 OBJ: Calculate the concentration of a metal ion in equilibrium with a complex ion (Example 17.9) TOP: solubility | complex ion equilibria KEY: complex ion formation | equilibrium calculations with Kf MSC: general chemistry 100 Which of the following insoluble salts will dissolve upon reaction with excess ammonia? A) BaSO4 B) CaCO3 C) PbSO4 D) HgS E) AgCl ANS: OBJ: 17.10) KEY: E PTS: DIF: easy REF: 17.6 Predict whether a precipitate will form in the presence of the complex ion (Example TOP: solubility | complex ion equilibria complex ions and solubility MSC: general chemistry 101 Which sparingly soluble salt will exhibit the highest solubility at low pH’s? A) PbS (Ksp = 2.5  10-27) B) MnS (Ksp = 2.5  10-10) C) HgS (Ksp = 1.6  10-52) D) NiS (Ksp =  10-9) E) ZnS (Ksp = 1.1  10-21) ANS: D PTS: DIF: easy REF: 17.6 OBJ: Predict whether a precipitate will form in the presence of the complex ion (Example 17.10) TOP: solubility | complex ion equilibria 102 The figure below represents the results of adding NH3 to a saturated solution of an ionic compound Which of the following could the ionic compound be? A) AgCl or CaF2 B) CaF2 C) Mg(OH)2 D) AgCl E) SrCO3 ANS: OBJ: 17.10) KEY: D PTS: DIF: easy REF: 17.6 Predict whether a precipitate will form in the presence of the complex ion (Example TOP: solubility | complex ion equilibria complex ions and solubility MSC: general chemistry 103 What will happen if 50.0 mL of 0.022 M Na2S2O3, 50.0 mL of 0.010 M AgNO3, and 50.0 mL of 0.097 M KCl are mixed together? For AgCl, Ksp = 1.8  10–10; for Ag(S2O3)23–, Kf = 2.9  1013 A) A precipitate of Ag2S2O3 will form B) A precipitate of KNO3 will form C) No precipitate will form because silver(I) ion exists predominantly as Ag+ D) No precipitate will form because silver(I) ion exists predominantly in the complex Ag(S2O3)23– E) A precipitate of AgCl will form ANS: OBJ: 17.10) KEY: D PTS: DIF: difficult REF: 17.6 Predict whether a precipitate will form in the presence of the complex ion (Example TOP: solubility | complex ion equilibria complex ions and solubility MSC: general chemistry 104 Given the two equilibria below, Ag+(aq) + 2NH3(aq); Kd = 5.9  10–8 Ag(NH3)2+(aq) AgCN(s) Ag+(aq) + CN(aq); Ksp = 2.2  10 16 what is Kc for the following equilibrium? AgCN(s) + 2NH3(aq) Ag(NH3)2+(aq) + CN–(aq) A) 3.7  10 9 B) 1.3  10 23 C) 2.7  10 D) 1.4  10 17 E) 5.9  10 8 ANS: A PTS: DIF: easy REF: 17.6 OBJ: Calculate the solubility of a slightly soluble ionic compound in a solution of the complex ion (Example 17.11) TOP: solubility | complex ion equilibria 105 Given the following equilibrium constants, 8 AgIO3 Ksp = 3.1  10 Ag(NH3)2+ Kf = 1.7  10 determine Kc for the dissolution of the sparingly soluble salt AgIO3 in aqueous ammonia (shown below) AgIO3(s) + 2NH3(aq) A) 5.3  10 1 B) 1.8  10 15 C) 5.5  10 14 D) 1.9 E) 1.7  10 Ag(NH3)2+(aq) + IO3–(aq) ANS: A PTS: DIF: easy REF: 17.6 OBJ: Calculate the solubility of a slightly soluble ionic compound in a solution of the complex ion (Example 17.11) TOP: solubility | complex ion equilibria 106 What is the molar solubility of nickel(II) sulfide in 0.053 M KCN? For NiS, Ksp = 3.0  10– 19 ; for Ni(CN)42–, Kf = 1.0  1031 A) 5.5  10–10 M B) 5.3  10–2 M C) 1.5  10–19 M D) 1.3  10–2 M E) 2.2  10–5 M ANS: D PTS: DIF: difficult REF: 17.6 OBJ: Calculate the solubility of a slightly soluble ionic compound in a solution of the complex ion (Example 17.11) TOP: solubility | complex ion equilibria KEY: complex ion formation | equilibrium calculations with Kf MSC: general chemistry 107 What is the molar solubility of zinc hydroxide at pH 12.40? For Zn(OH)2, Ksp = 2.1  10–16; for Zn(OH)42–, Kf = 2.8  1015 A) 9.4  10–26 M B) 1.5  10–2 M C) 3.7  10–4 M D) 3.7  10–6 M E) 1.4  10–8 M ANS: C PTS: DIF: difficult REF: 17.6 OBJ: Calculate the solubility of a slightly soluble ionic compound in a solution of the complex ion (Example 17.11) TOP: solubility | complex ion equilibria KEY: complex ion formation | equilibrium calculations with Kf MSC: general chemistry 108 Which of the following statements concerning the separation of metal ions into Analytical Groups I-V is/are correct? Only the least soluble sulfides will precipitate in an acidic solution of H2S K+ and Na+ are precipitated in the last step of the separation scheme The formation of a precipitate with the addition of dilute HCl(aq) indicates the original solution contains all of the ions of Analytical Group I (the ions which precipitate as chlorides) A) only B) only C) only D) and E) 1, 2, and ANS: A PTS: DIF: easy REF: 17.7 OBJ: Describe the main outline of the sulfide scheme for qualitative analysis TOP: solubility | applications of solubility equilibria 109 Which of the following statements concerning the separation of metal ions into Analytical Groups I-V is/are correct? A) B) C) D) E) The substitution of dilute Zn(Cl)2 for dilute HCl in step one, the precipitation of the Analytical Group I metal ions as chloride salts, will have no effect on the rest of the analysis Group I ions cannot be precipitated using this scheme In the filtration stages, the filtrate is the solid material that is removed from the mixture by filtration only only only and 1, 2, and ANS: B PTS: DIF: easy REF: 17.7 OBJ: Describe the main outline of the sulfide scheme for qualitative analysis TOP: solubility | applications of solubility equilibria 110 In the qualitative analysis scheme for metal ions, how are the Analytical Group III cations separated from the cations of Analytical Groups IV and V? A) by addition of H2S in acidic solution, forming insoluble metal sulfides B) by addition of (NH4)2CO3 or (NH4)3PO4, forming insoluble metal carbonates or phosphates C) by addition of H2SO4, forming insoluble metal sulfates D) by addition of HCl, forming insoluble metal chlorides E) by addition of H2S in basic solution, forming insoluble metal sulfides or hydroxides ANS: OBJ: TOP: KEY: E PTS: DIF: easy REF: 17.7 Describe the main outline of the sulfide scheme for qualitative analysis solubility | applications of solubility equilibria qualitative analysis of metal ions MSC: general chemistry 111 What is the effect of substituting soluble metal salts such as NaCl and K2CO3 for HCl or (NH4)2CO3 in the qualitative analysis scheme for separating the five Analytical Groups? A) You can no longer tell if your original sample contained Na+ or K+ B) There is no effect on the analysis since Na+ and K+ not form a precipitate C) The NaCl and K2CO3 are not pure, analytical grade materials D) Potassium ion forms a precipitate with sulfide ion E) Na+ and K+ react violently with acids such as H2S, producing highly flammable and potentially explosive hydrogen gas ANS: A PTS: DIF: easy REF: 17.7 OBJ: Describe the main outline of the sulfide scheme for qualitative analysis TOP: solubility | applications of solubility equilibria 112 In the sulfide scheme for qualitative analysis, the cations of Analytical Group IV are precipitated as phosphates or carbonates Analytical Group IV consists of A) alkaline earth elements B) the halogens C) alkali metals D) transition metals having +2 ions E) none of these ANS: OBJ: TOP: KEY: A PTS: DIF: moderate REF: 17.7 Describe the main outline of the sulfide scheme for qualitative analysis solubility | applications of solubility equilibria qualitative analysis of metal ions MSC: general chemistry 113 Consider a solution containing the following cations: Na+, Hg2+, Mn2+, Al3+ and Ag+ Treatment of the solution with dilute, HCl followed by saturation with H2S, results in formation of precipitate(s) Which ions still remain in solution (did not precipitate)? A) Na+, Hg2+, Al3+ B) Na+ only C) Ag+ and Hg2+ D) Ag+ only E) Na+, Al3+, and Mn2+ ANS: OBJ: TOP: KEY: E PTS: DIF: moderate REF: 17.7 Describe the main outline of the sulfide scheme for qualitative analysis solubility | applications of solubility equilibria qualitative analysis of metal ions MSC: general chemistry 114 The following reaction represents a step in the separation of which analytical group of cations? Hg22+(aq) + 2Cl–(aq)  Hg2Cl2(s) A) Analytical Group II B) C) D) E) Analytical Group I Analytical Group V Analytical Group IV Analytical Group III ANS: OBJ: TOP: KEY: B PTS: DIF: easy REF: 17.7 Describe the main outline of the sulfide scheme for qualitative analysis solubility | applications of solubility equilibria qualitative analysis of metal ions MSC: general chemistry 115 The following reaction represents a step in the separation of which analytical group of cations? Cu2+(aq) + S2–(aq)  CuS(s) A) Analytical Group I B) C) D) E) Analytical Group III Analytical Group V Analytical Group IV Analytical Group II ANS: OBJ: TOP: KEY: E PTS: DIF: easy REF: 17.7 Describe the main outline of the sulfide scheme for qualitative analysis solubility | applications of solubility equilibria qualitative analysis of metal ions MSC: general chemistry