Deck 17: Aqueous Ionic Equilibrium

Question 1

If the pKa of HCHO₂ is 3.74 and the pH of an HCHO₂/NaCHO₂ solution is 3.11,which of the following is TRUE?

A) [HCHO₂] < [NaCHO₂]
B) [HCHO₂] = [NaCHO₂]
C) [HCHO₂] << [NaCHO₂]
D) [HCHO₂] > [NaCHO₂]
E) It is not possible to make a buffer of this pH from HCHO₂ and NaCHO₂.

Answer 1

[HCHO₂] > [NaCHO₂]

Question 2

A 1.00 L buffer solution is 0.250 M in HF and 0.250 M in LiF.Calculate the pH of the solution after the addition of 0.150 moles of solid LiOH.Assume no volume change upon the addition of base.The K_a for HF is 3.5 × 10^-4.

A) 3.46
B) 4.06
C) 2.85
D) 3.63
E) 4.24

Answer 2

4.06

Question 3

Calculate the pH of a solution formed by mixing 250.0 mL of 0.15 M NH₄Cl with 200.0 mL of 0.12 M NH₃.The K_b for NH₃ is 1.8 × 10^-5.

A) 9.06
B) 9.45
C) 4.55
D) 4.74
E) 9.26

Answer 3

9.06

Question 4

If the pKa of HCHO₂ is 3.74 and the pH of an HCHO₂/NaCHO₂ solution is 3.74,which of the following is TRUE?

A) [HCHO₂] > [NaCHO₂]
B) [HCHO₂] = [NaCHO₂]
C) [HCHO₂] < [NaCHO₂]
D) [HCHO₂] < <[NaCHO₂]
E) It is not possible to make a buffer of this pH from HCHO₂ and NaCHO₂.

Question 5

If the pKa of HCHO₂ is 3.74 and the pH of an HCHO₂/NaCHO₂ solution is 3.89,which of the following is TRUE?

A) [HCHO₂] < [NaCHO₂]
B) [HCHO₂] = [NaCHO₂]
C) [HCHO₂] > [NaCHO₂]
D) [HCHO₂] >> [NaCHO₂]
E) It is not possible to make a buffer of this pH from HCHO₂ and NaCHO₂.

Question 6

Calculate the pH of a solution formed by mixing 150.0 mL of 0.10 M HC₇H₅O₂ with 100.0 mL of 0.30 M NaC₇H₅O₂.The K_a for HC₇H₅O₂ is 6.5 × 10^-5.

A) 4.19
B) 9.69
C) 4.49
D) 4.31
E) 10.51

Question 7

In the blood,the concentration of bicarbonate is ________ times higher than the concentration of carbonic acid.

A) 15
B) 25
C) 30
D) 10
E) 20

Question 8

A 1.00 L buffer solution is 0.150 M in HC₇H₅O₂ and 0.250 M in LiC₇H₅O₂.Calculate the pH of the solution after the addition of 100.0 mL of 1.00 M HCl.The K_a for HC₇H₅O₂ is 6.5 × 10^-5.

A) 4.19
B) 5.03
C) 4.41
D) 3.34
E) 3.97

Question 9

A 1.50 L buffer solution is 0.250 M in HF and 0.250 M in NaF.Calculate the pH of the solution after the addition of 0.100 moles of solid NaOH.Assume no volume change upon the addition of base.The K_a for HF is 3.5 × 10^-4.

A) 3.22
B) 3.82
C) 3.69
D) 3.09
E) 4.46

Question 10

Identify the structure for antifreeze.

A) CH₃CH₂OCH₂CH₃
B) CH₃OH
C) HOCH₂CH₂OH
D) CH₃CH₂OH
E) (CH₃)₂CHOH

Question 11

Calculate the pH of a buffer that is 0.225 M HC₂H₃O₂ and 0.162 M KC₂H₃O₂.The K_a for HC₂H₃O₂ is 1.8 × 10^-5.

A) 4.89
B) 9.11
C) 4.74
D) 9.26
E) 4.60

Question 12

When titrating a weak monoprotic acid with NaOH at 25°C,the

A) pH will be less than 7 at the equivalence point.
B) pH will be equal to 7 at the equivalence point.
C) pH will be greater than 7 at the equivalence point.
D) titration will require more moles of base than acid to reach the equivalence point.
E) titration will require more moles of acid than base to reach the equivalence point.

Question 13

A 1.50 L buffer solution is 0.250 M in HF and 0.250 M in NaF.Calculate the pH of the solution after the addition of 0.0500 moles of solid NaOH.Assume no volume change upon the addition of base.The K_a for HF is 3.5 × 10^-4.

A) 3.34
B) 3.46
C) 3.57
D) 3.63
E) 2.89

Question 14

When titrating a strong monoprotic acid and KOH at 25°C,the

A) pH will be less than 7 at the equivalence point.
B) pH will be greater than 7 at the equivalence point.
C) titration will require more moles of base than acid to reach the equivalence point.
D) pH will be equal to 7 at the equivalence point.
E) titration will require more moles of acid than base to reach the equivalence point.

Question 15

Which of the following is TRUE?

A) The equivalence point is where the amount of acid equals the amount of base during any acid-base titration.
B) At the equivalence point, the pH is always 7.
C) An indicator is not pH sensitive.
D) A titration curve is a plot of pH vs. the [base]/[acid] ratio.
E) None of the above is true.

Question 16

Calculate the pH of a solution formed by mixing 250.0 mL of 0.15 M NH₄Cl with 100.0 mL of 0.20 M NH₃.The K_b for NH₃ is 1.8 × 10^-5.

A) 9.13
B) 9.25
C) 9.53
D) 4.74
E) 8.98

Question 17

Which of the following is TRUE?

A) An effective buffer has a [base]/[acid] ratio in the range of 10 - 100.
B) A buffer is most resistant to pH change when [acid] = [conjugate base]
C) An effective buffer has very small absolute concentrations of acid and conjugate base.
D) A buffer cannot be destroyed by adding too much strong base. It can only be destroyed by adding too much strong acid.
E) None of the above is true.

Question 18

Define buffer capacity.

A) Buffer capacity is the amount of acid or base that can be added to a buffer without destroying its effectiveness.
B) Buffer capacity is the amount of acid that can be added until all of the base is used up.
C) Buffer capacity is the amount of base that can be added until all of the acid is used up.
D) Buffer capacity is the amount of acid that can be added until all of the acid is used up.
E) Buffer capacity is the amount of base that can be added until all of the base is used up.

Question 19

A 1.00 L buffer solution is 0.250 M in HF and 0.250 M in NaF.Calculate the pH of the solution after the addition of 100.0 mL of 1.00 M HCl.The K_a for HF is 3.5 × 10^-4.

A) 3.09
B) 4.11
C) 3.82
D) 3.46
E) 2.78

Question 20

Calculate the pH of a solution formed by mixing 250.0 mL of 0.15 M HCHO₂ with 100.0 mL of 0.20 M LiCHO₂.The K_a for HCHO₂ is 1.8 × 10^-4.

A) 3.87
B) 3.74
C) 10.53
D) 3.47
E) 10.13

Question 21

Determine the molar solubility of BaF₂ in pure water.K_sp for BaF₂ = 2.45 × 10^-5.

A) 1.83 × 10^-2 M
B) 1.23 × 10^-5 M
C) 2.90 × 10^-2 M
D) 4.95 × 10^-3 M
E) 6.13 × 10^-6 M

Question 22

Determine the molar solubility of AgI in pure water.K_sp (AgI)= 8.51 × 10^-17.

A) 9.22 × 10^-9 M
B) 4.26 × 10^-17 M
C) 8.51 × 10^-17 M
D) 2.77 × 10^-6 M
E) 4.40 × 10^-6 M

Question 23

The molar solubility of CuI is 2.26 × 10^-6 M in pure water.Calculate the K_sp for CuI.

A) 5.11 × 10^-12 M
B) 4.52 × 10^-6 M
C) 1.50 × 10^-3 M
D) 4.62 × 10^-17 M
E) 1.02 × 10^-11 M

Question 24

Determine the solubility of the ions that is calculated from the Ksp for Na₃PO₄.

A) S⁴
B) 27S³
C) 3S²
D) 27S⁴
E) 9S⁴

Question 25

A 100.0 mL sample of 0.10 M NH₃ is titrated with 0.10 M HNO₃.Determine the pH of the solution after the addition of 150.0 mL of HNO₃.The K_b of NH₃ is 1.8 × 10^-5.

A) 1.70
B) 6.44
C) 7.56
D) 12.30
E) 2.30

Question 26

The molar solubility of ZnS is 1.6 × 10^-12 M in pure water.Calculate the K_sp for ZnS.

A) 8.0 × 10^-13 M
B) 3.2 × 10^-12 M
C) 1.6 × 10^-35 M
D) 2.6 × 10^-24 M
E) 6.80 × 10^-5 M

Question 27

A 100.0 mL sample of 0.10 M NH₃ is titrated with 0.10 M HNO₃.Determine the pH of the solution after the addition of 200.0 mL of HNO₃.The K_b of NH₃ is 1.8 × 10^-5.

A) 6.44
B) 1.48
C) 2.00
D) 12.52
E) 12.00

Question 28

Determine the molar solubility of MgCO₃ in pure water.K_sp (MgCO₃)= 6.82 × 10^-6.

A) 6.82 × 10^-6 M
B) 3.41 × 10^-6 M
C) 4.65 × 10^-3 M
D) 2.61 × 10^-3 M
E) 3.25 × 10^-4 M

Question 29

When a diprotic acid is titrated with a strong base,and the K_a1 and K_a2 are significantly different,then the pH vs.volume plot of the titration will have

A) a pH of 7 at the equivalence point.
B) two equivalence points below 7.
C) no equivalence point.
D) one equivalence point.
E) two distinct equivalence points.

Question 30

Determine the molar solubility of PbSO₄ in pure water.K_sp (PbSO₄)= 1.82 × 10^-8.

A) 1.82 × 10^-8 M
B) 1.35 × 10^-4 M
C) 9.1 × 10^-9 M
D) 3.31 × 10^-16 M
E) 4.48 × 10^-4 M

Question 31

When titrating a weak base with a monoprotic acid at 25°C,the

A) pH will be 7 at the equivalence point.
B) pH will be greater than 7 at the equivalence point.
C) titration will require more moles of the base than acid to reach the equivalence point.
D) titration will require more moles of acid than base to reach the equivalence point.
E) pH will be less than 7 at the equivalence point.

Question 32

Determine the molar solubility of Fe(OH)₂ in pure water.K_sp for Fe(OH)₂= 4.87 × 10^-17.

A) 2.44 × 10^-17 M
B) 1.62 × 10^-17 M
C) 4.03 × 10^-9 M
D) 3.65 × 10^-6 M
E) 2.30 × 10^-6 M

Question 33

A 100.0 mL sample of 0.10 M NH₃ is titrated with 0.10 M HNO₃.Determine the pH of the solution after the addition of 100.0 mL of HNO₃.The K_b of NH₃ is 1.8 × 10^-5.

A) 6.58
B) 10.56
C) 8.72
D) 3.44
E) 5.28

Question 34

Determine the solubility of the ions that is calculated from the Ksp for Mg₂CO₃.

A) 2S³
B) S³
C) 4S³
D) S²
E) 2S²

Question 35

100.0 mL sample of 0.10 M NH₃ is titrated with 0.10 M HNO₃.Determine the pH of the solution before the addition of any HNO₃.The K_b of NH₃ is 1.8 × 10^-5.

A) 4.74
B) 9.26
C) 11.13
D) 13.00
E) 12.55

Question 36

When titrating a weak base with HCl at 25°C,the

A) pH will be less than 7 at the equivalence point.
B) pH will be equal to 7 at the equivalence point.
C) pH will be greater than 7 at the equivalence point.
D) titration will require more moles of base than acid to reach the equivalence point.
E) titration will require more moles of acid than base to reach the equivalence point.

Question 37

Determine the molar solubility for Al(OH)₃ in pure water.K_sp for Al(OH)₃ = 1.3 × 10^-33.

A) 3.6 × 10^-12 M
B) 2.2 × 10^-10 M
C) 4.8 × 10^-35 M
D) 2.6 × 10^-9 M
E) 6.0 × 10^-19 M

Question 38

A 100.0 mL sample of 0.10 M NH₃ is titrated with 0.10 M HNO₃.Determine the pH of the solution after the addition of 50.0 mL of HNO₃.The K_b of NH₃ is 1.8 × 10^-5.

A) 4.74
B) 7.78
C) 7.05
D) 9.26
E) 10.34

Question 39

Determine the molar solubility for Pb₃(PO₄)₂ in pure water.Ksp for Pb₃(PO₄)₂ is 1.0 × 10^-54.

A) 4.1 × 10^-28 M
B) 5.8 × 10^-10 M
C) 1.1 × 10^-11 M
D) 6.2 × 10^-12 M
E) 1.0 × 10^-54 M

Question 40

Determine the molar solubility for Zn(OH)₂ in pure water.Ksp for Zn(OH)₂ is 3.00 × 10^-17.

A) 3.0 × 10^-17 M
B) 7.5 × 10^-18 M
C) 3.11 × 10^-6 M
D) 1.96 × 10^-6 M
E) 5.5 × 10^-19 M

Question 41

Identify the ion that is less soluble in acidic water.

A) NH₄⁺
B) S^2-
C) CO₃^2-
D) OH^-
E) CN^-

Question 42

The molar solubility of Ba₃(PO₄)₂ is 8.89 × 10^-9 M in pure water.Calculate the K_sp for Ba₃(PO₄)₂.

A) 4.94 × 10^-49 M
B) 5.55 × 10^-41 M
C) 5.33 × 10^-37 M
D) 8.16 × 10^-31 M
E) 6.00 × 10^-39 M

Question 43

Give the mathematical relationship for an unsaturated solution in comparing Q with K_sp.

A) Q > K_sp
B) Q < K_sp
C) Q = K_sp
D) Q ≠ K_sp
E) none of the above

Question 44

A solution contains 0.036 M Cu²⁺ and 0.044 M Fe²⁺.A solution containing sulfide ions is added to selectively precipitate one of the metal ions from solution.At what concentration of sulfide ion will a precipitate begin to form? What is the identity of the precipitate? K_sp(CuS)= 1.3 × 10^-36,K_sp(FeS)= 6.3 × 10^-18.

A) 1.4 × 10^-16 M, FeS
B) 3.6 × 10^-35 M, CuS
C) 3.6 × 10^-35 M, FeS
D) 1.4 × 10^-16 M, CuS
E) No precipitate will form at any concentration of sulfide ion.

Question 45

A solution contains 0.021 M Cl⁻ and 0.017 M I⁻.A solution containing copper(I)ions is added to selectively precipitate one of the ions.At what concentration of copper(I)ion will a precipitate begin to form? What is the identity of the precipitate? K_sp(CuCl)= 1.0 × 10^-6,K_sp(CuI)= 5.1 × 10^-12.

A) 3.0 × 10^-10 M, CuI
B) 3.0 × 10^-10 M, CuCl
C) 4.8 × 10^-5 M, CuCl
D) 4.8 × 10^-5 M, CuI
E) No precipitate will form at any concentration of copper(I).

Question 46

Determine the molar solubility of Al(OH)₃ in a solution containing 0.0500 M AlCl₃. K_sp (Al(OH)₃)= 1.3 × 10^-33.

A) 2.6 × 10^-9 M
B) 5.2 × 10^-31 M
C) 2.6 × 10^-32 M
D) 9.87 × 10^-12 M
E) 6.5 × 10^-35 M

Question 47

A solution containing CaCl₂ is mixed with a solution of Li₂C₂O₄ to form a solution that is 2.1 × 10^-5 M in calcium ion and 4.75 × 10^-5 M in oxalate ion.What will happen once these solutions are mixed? K_sp (CaC₂O₄)= 2.3 × 10^-9.

A) A precipitate will form since Q > K_sp for calcium oxalate.
B) Nothing will happen since both calcium chloride and lithium oxalate are soluble compounds.
C) Nothing will happen since calcium oxalate is extremely soluble.
D) Nothing will happen since K_sp > Q for all possible precipitants.
E) There is not enough information to determine.

Question 48

A sample contains MgNH₄(PO₄)₂, Sb₂S₃,KBr,Cr(OH)₃,and PbCl₂.Identify the precipitate after the addition of 6 M HCl; then H₂S and 0.2 M HCl; and then OH^- to a pH of 8.

A) MgNH₄(PO₄)₂
B) Sb₂S₃
C) KBr
D) Cr(OH)₃
E) PbCl₂

Question 49

A sample contains MgNH₄(PO₄)₂, Sb₂S₃,KBr,Cr(OH)₃,and PbCl₂.Identify the precipitate after the addition of 6 M HCl; then H₂S and 0.2 M HCl.

A) MgNH₄(PO₄)₂
B) Sb₂S₃
C) KBr
D) Cr(OH)₃
E) PbCl₂

Question 50

A sample contains MgNH₄(PO₄)₂, Sb₂S₃,KBr,Cr(OH)₃,and PbCl₂.Identify the precipitate after the addition of 6 M HCl; then H₂S and 0.2 M HCl; then OH^- to a pH of 8; and then (NH₄)₂HPO₄ with NH₃.

A) MgNH₄(PO₄)₂
B) Sb₂S₃
C) KBr
D) Cr(OH)₃
E) PbCl₂

Question 51

Determine the molar solubility of AgBr in a solution containing 0.200 M NaBr. K_sp (AgBr)= 7.7 × 10^-13.

A) 8.8 × 10^-7 M
B) 1.54 × 10^-13 M
C) 5.8 × 10^-5 M
D) 3.8 × 10^-12 M
E) 0.200 M

Question 52

Give the equation for a saturated solution in comparing Q with K_sp.

A) Q > K_sp
B) Q < K_sp
C) Q = K_sp
D) Q ≠ K_sp
E) none of the above

Question 53

Determine the molar solubility of AgBr in a solution containing 0.150 M NaBr. K_sp (AgBr)= 7.7 × 10^-13.

A) 8.8 × 10^-7 M
B) 3.9 × 10^-13 M
C) 5.8 × 10^-5 M
D) 5.1 × 10^-12 M
E) 0.150 M

Question 54

A solution containing CaCl₂ is mixed with a solution of Li₂C₂O₄ to form a solution that is 3.5 × 10^-4 M in calcium ion and 2.33 × 10^-4 M in oxalate ion.What will happen once these solutions are mixed? K_sp (CaC₂O₄)= 2.3 × 10^-9.

A) Nothing will happen since both calcium chloride and lithium oxalate are soluble compounds.
B) Nothing will happen K_sp > Q for all possible precipitants.
C) A precipitate will form as calcium oxalate is not soluble to any extent.
D) A precipitate will form since Q > K_sp for calcium oxalate.
E) There is not enough information to determine.

Question 55

Determine the molar solubility of BaF₂ in a solution containing 0.0750 M LiF. K_sp (BaF₂)= 1.7 × 10^-6.

A) 2.3 × 10^-5 M
B) 8.5 × 10^-7 M
C) 1.2 × 10^-2 M
D) 0.0750 M
E) 3.0 × 10^-4 M

Question 56

The difference between Q and Ksp is

A) Q is greater than Ksp.
B) no difference.
C) K_sp is the value of the product at equilibrium and Q is the value of the product under any condition.
D) Ksp is greater than Q.
E) Q is the value of the product at equilibrium and K_sp is the value of the product under any condition.

Question 57

A solution containing AgNO₃ is mixed with a solution of NaCl to form a solution that is 0.10 M in AgNO₃ and 0.075 M in NaCl.What will happen once these solutions are mixed? K_sp (AgCl)= 1.77 × 10^-10.

A) Nothing will happen since the molar solubility of AgCl is higher than the solution concentrations.
B) Silver chloride will precipitate out of solution, leaving an unsaturated solution of AgCl.
C) Silver chloride will precipitate out of solution, leaving a saturated AgCl solution.
D) Nothing will happen since NaCl and AgNO₃ are both soluble compounds.
E) There is not enough information to say anything about this solution.

Question 58

A sample contains MgNH₄(PO₄)₂, Sb₂S₃,KBr,Cr(OH)₃,and PbCl₂.Identify the precipitate after the addition of 6 M HCl.

A) MgNH₄(PO₄)₂
B) Sb₂S₃
C) KBr
D) Cr(OH)₃
E) PbCl₂

Question 59

Give the equation for a supersaturated solution in comparing Q with K_sp.

A) Q > K_sp
B) Q < K_sp
C) Q = K_sp
D) Q ≠ K_sp
E) none of the above

Question 60

The molar solubility of Ag₂S is 1.26 × 10^-16 M in pure water.Calculate the K_sp for Ag₂S.

A) 1.59 × 10^-32 M
B) 1.12 × 10^-8 M
C) 6.81 × 10^-63 M
D) 3.78 × 10^-12 M
E) 8.00 × 10^-48 M

Question 61

Calculate K. AgI(s)⇌ Ag⁺(aq)+ I^-(aq)K_sp = 8.5 × 10^-17
Ag⁺(aq)+ 2 NH₃(aq)⇌ Ag(NH₃)₂²⁺(aq)K_f = 1.7 × 10⁷
AgI(s)+ 2 NH₃(aq)⇌ Ag(NH₃)₂²⁺(aq)+ I^-(aq)K = ?

A) 1.7 × 10⁷
B) 1.4 × 10^-9
C) 5.0 × 10^-24
D) 2.0 × 10²³
E) 6.9 × 10⁸

Question 62

Calculate the pH of a solution that is 0.210 M in nitrous acid (HNO₂)and 0.290 M in potassium nitrite (KNO₂).The acid dissociation constant of nitrous acid is 4.50 × 10^-4.

A) 3.487
B) 3.210
C) 13.86
D) 10.51
E) 4.562

Question 63

What is the pH of a buffer solution that is 0.211 M in lactic acid and 0.111 M in sodium lactate? The K_a of lactic acid is 1.4 × 10^-4.

A) 14.28
B) 10.43
C) 5.48
D) 3.57
E) 4.13

Question 64

A solution contains 2.2 × 10^-3 M in Cu²⁺ and 0.33 M in LiCN.If the K_f for Cu(CN)₄^2- is 1.0 × 10²⁵,how much copper ion remains at equilibrium?

A) 3.8 × 10^-24 M
B) 1.9 × 10^-26 M
C) 6.7 × 10^-28 M
D) 2.9 × 10^-27 M
E) 4.6 × 10^-25 M

Question 65

A solution contains 3.8 × 10^-2 M in Al³⁺ and 0.29 M in NaF.If the K_f for AlF₆^3- is 7 × 10¹⁹,how much aluminum ion remains at equilibrium?

A) 1.1 × 10^-19 M
B) 3.1 × 10^-22 M
C) 9.1 × 10^-19 M
D) 1.9 × 10^-21 M
E) 4.4 × 10^-20 M

Question 66

Give the expression for K_f for Fe(CN)₆^3-.

A)
B)
C)
D) [Fe³⁺] [CN^-]⁶
E)

Question 67

Which one of the following statements is TRUE?

A) A buffer is an aqueous solution composed of two weak acids.
B) A buffer can absorb an unlimited amount of acid.
C) A buffer resists pH change by neutralizing added acids and bases.
D) A buffer does not change pH when strong acid or base is added.
E) None of the above are true.

Question 68

Identify a good buffer.

A) small amounts of both a weak acid and its conjugate acid
B) significant amounts of both a strong base and a strong acid
C) small amounts of both a strong acid and a conjugate acid
D) significant amounts of both a weak acid and a strong acid
E) significant amounts of both a weak acid and its conjugate base

Question 69

Identify the cation that is NOT amphoteric.

A) Fe²⁺
B) Cr³⁺
C) Zn²⁺
D) Pb²⁺
E) Sn²⁺

Question 70

Which of the following solutions is a good buffer system?

A) a solution that is 0.10 M HC₂H₃O₂ and 0.10 M LiC₂H₃O₂
B) a solution that is 0.10 M HBr and 0.10 M KC₂H₃O₂
C) a solution that is 0.10 M HI and 0.10 M NH₄⁺
D) a solution that is 0.10 M NaOH and 0.10 M KOH
E) None of the above is a buffer system.

Question 71

Give the expression for K_f for Co(SCN)₄^2-.

A)
B)
C)
D) [Co⁴⁺] [SCN^-]⁴
E)

Question 72

Calculate the pH of a solution that is 0.295 M in sodium formate (NaHCO₂)and 0.205 M in formic acid (HCO₂H).The K_a of formic acid is 1.77 × 10^-4.

A) 3.910
B) 3.587
C) 13.84
D) 10.10
E) 4.963

Question 73

Calculate K. Cu(OH)₂(aq)⇌ Cu²⁺(aq)+ 2 OH^-(aq)K_sp = 1.6 × 10^-19
Cu²⁺(aq)+ 4 NH₃(aq)⇌ Cu(NH₃)₄²⁺(aq)K_f = 1.7 × 10¹³
Cu(OH)₂(aq)+ 4 NH₃(aq)⇌ Cu(NH₃)₄²⁺(aq)+ 2 OH^-(aq)K = ?

A) 1.06 × 10³²
B) 3.7 × 10⁵
C) 9.4 × 10^-33
D) 2.7 × 10^-6
E) 1.7 × 10¹³

Question 74

A complex ion contains

A) a central nonmetal ion bound to one or more ligands.
B) an anion bound to water.
C) water bound to one or more ligands.
D) a central metal ion bound to one or more ligands.
E) ammonia bound to water.

Question 75

Which of the following solutions is a good buffer system?

A) a solution that is 0.10 M NaCl and 0.10 M HCl
B) a solution that is 0.10 M HCN and 0.10 M LiCN
C) a solution that is 0.10 M LiOH and 0.10 M HNO₃
D) a solution that is 0.10 M HNO₃ and 0.10 M NaNO₃
E) a solution that is 0.10 M HCN and 0.10 M NaBr

Question 76

Animals will lick up ethylene glycol (antifreeze)due to its sweet taste.The antidote for ethylene glycol poisoning is the administration of

A) ethyl alcohol ( alcoholic drinks).
B) methyl alcohol (window washer fluid).
C) mineral oil (laxative).
D) vinegar.
E) sodium carbonate (washing soda).

Question 77

What is the pH of a buffer solution that is 0.255 M in hypochlorous acid (HClO)and 0.333 M in sodium hypochlorite? The K_a of hypochlorous acid is 3.8 × 10^-8.

A) 13.88
B) 6.46
C) 8.49
D) 7.30
E) 7.54

Question 78

An important buffer in the blood is a mixture of

A) potassium chloride and hydrochloric acid.
B) hydrochloric acid and sodium hydroxide.
C) carbonic acid and bicarbonate ion.
D) phosphoric acid and bicarbonate ion.
E) acetic acid and phosphate ion.

Question 79

A sample contains MgNH₄(PO₄)₂, Sb₂S₃,KBr,Cr(OH)₃,and PbCl₂.Identify the soluble ions after the addition of 6 M HCl; then H₂S and 0.2 M HCl; then OH^- to a pH of 8; and then (NH₄)₂HPO₄ with NH₃.

A) MgNH₄(PO₄)₂
B) Sb₂S₃
C) KBr
D) Cr(OH)₃
E) PbCl₂

Question 80

What is the pH of a solution prepared by mixing 30.00 mL of 0.10 M CH₃CO₂H with 30.00 mL of 0.030 M CH₃CO₂K? Assume that the volume of the solutions are additive and that K_a = 1.8 × 10^-5 for CH₃CO₂H.

A) 2.87
B) 4.22
C) 4.75
D) 5.27