University of South Florida

COURSE TITLE: CHM 2046

1)The molar solubility of PbI2 is 1.52 ´10^–3 M. Calculate the value of Ksp for PbI2.

A)   3.51 ×10- 9

B)     4.62 ×10- 6

C)     1.40 ×10- 8

D)   1.52 ×10- 3

E)     none of these

 

 

 

 

 

2. The concentration of OH^– in a saturated solution of Mg(OH)2 is 3.63 ´ 10^–4 M. The Ksp of Mg(OH)2 is

A)  6.6 ×10- 8

B)     4.8 ×10- 11

C)     1.3 ×10- 7

D)   3.6 ×10- 4

E)     2.4 ×10- 11

 

                                              

 

 

3. The solubility of CaSO4 in pure water at 0^oC is 1.14 gram(s) per liter. The value of the solubility product is

A)   8.37 ×10- 3

B)     1.14 ×10- 3

C)     9.15 ×10- 2

D)   7.01 ×10- 5

E)     none of these

 

 

                                              

 

 

4. It is observed that 7.50 mmol of BaF2 will dissolve in 1.0 L of water. Use these data to calculate the value of Ksp for barium fluoride.

A)   1.1 ×10- 4

B)     4.2 ×10- 7

C)     1.7 ×10- 6

D)   2.2 ×10- 4

E)     5.6 ×10- 5

 

 

 

 

 

5. The solubility in mol/L of Ag2CrO4 is 1.8 ´ 10^–4 M. Calculate the Ksp for this compound.

A)   6.5 ×10- 8

B)     1.8 ×10- 4

C)     2.3 ×10- 11

D)   5.8 ×10- 12

E)     3.6 ×10- 4

 

 

 

 

 

6. The solubility of Cd(OH)2 in water is 1.67 ´ 10^–5 mol/L. The Ksp value for Cd(OH)2 is

A)   1.86 ×10- 14

B)     4.66 ×10- 15

C)     5.58 ×10- 10

D)   1.67 ×10- 5

E)     none of these

 

 

               

 

 

7. The solubility of silver phosphate, Ag3PO4, at 25°C is 1.60 ´ 10^–5 mol/L. What is the Ksp for the silver phosphate at 25°C?

A)   1.11 ×10- 13

B)     1.77 ×10- 18

C)     7.68 ×10- 10

D)   6.55 ×10- 20

E)     none of these

                                              

 

 

8.  

3    2,                                                                                                                       sp                 3   2

The solubility of an unknown salt, M Z at 25°C is 3.1 ×10- 7 mol/L. What is the K for M Z at 25°C?

A)   4.2 ×10- 23

B)     1.0 ×10- 24

C)     7.7 ×10- 32

D)   3.1 ×10- 31

E)     none of these

 

 

                                              

 

 

9.  

2,                                                                                                                       sp                     2

The solubility of an unknown salt, MZ at 25°C is 3.9 ×10- 4 mol/L. What is the K for MZ at 25°C?

A)   3.8 ×10- 9

B)     1.5 ×10- 7

C)     1.6 ×10- 9

D)   6.1 ×10- 7

E)     none of these

 

 

                                              

 

 

10.  

3,                                                                                                                       sp                     3

The solubility of an unknown salt, MZ at 25°C is 3.1 ×10- 5 mol/L. What is the K for MZ at 25°C?

A)   5.9 ×10- 10

B)     2.5 ×10- 17

C)     8.0 ×10- 13

D)   1.2 ×10- 13

E)     none of these

 

 

                                              

 

 

11. Barium carbonate has a measured solubility of 4.03 ´ 10^–5 at 25°C. Determine the Ksp.

A)   4.03 ×10- 5

B)     8.06 ×10- 5

C)     6.35 ×10- 3

D)  2.62 ×10- 13

E)     1.62 ×10- 9

 

 

                                              

 

 

12. A 300.0-mL saturated solution of copper(II) peroidate, Cu(IO4)2, contains 0.30 grams of dissolved salt. Determine the Ksp.

A)   1.0 ×10- 5

B)     2.0 ×10- 5

C)     2.2 ×10- 3

D)   4.5 ×10- 8

E)     1.2 ×10- 9

                                              

 

 

 

 

13. 

    

    The                in a saturated solution of                   is 5.93 ´ 10^–3 M. Calculate the Ksp for                 .

A)  4.12 ×10- 10

B)     3.71 ×10- 9

C)     2.09 ×10- 7

D)   1.98 ×10- 3

E)     none of these

 

 

               

 

 

14. The correct mathematical expression for finding the molar solubility (s) of Sn(OH)2 is:
    1. 2s² = Ksp
    2. 2s³ = Ksp
    3. 108s⁵ = Ksp
    4. 4s³ = Ksp
    5. 8s³ = Ksp

 

                                              

 

 

15. Find the solubility (in mol/L) of lead(II) chloride, PbCl2, at 25°C. Ksp = 1.59 ´ 10^–5.

A)   1.58 ×10- 2

B)     2.51 ×10- 2

C)     6.28 ×10- 17

D)   1.99 ×10- 3

E)     2.00 ×10- 2

 

               

 

 

16.  

4                                                                                              4         sp

Calculate the concentration of chromate ion, CrO ^2–, in a saturated solution of CaCrO (K = 7.08 ´ 10^–4).

A)    2.66 ×10- 2 M

B)     1.42 ×10- 3 M

C)     7.08 ×10- 4 M

D)    5.01 ×10- 7 M

E)     3.54 ×10- 4 M

 

 

               

 

 

17. Calculate the concentration of the silver ion in a saturated solution of silver chloride, AgCl (Ksp = 1.57 ´ 10^–10).

A)  1.57 ×10- 10

B)     1.25 ×10- 5

C)     2.46 ×10- 20

D)   3.14 ×10- 10

E)     none of these

                                              

 

 

18. Silver chromate, Ag2CrO4, has a Ksp of 8.96 ´ 10^–12. Calculate the solubility in mol/L of silver chromate.

A)    1.31 ×10- 4 M

B)     1.65 ×10- 4   M

C)     2.25 ×10- 12   M

D)    2.08 ×10- 4 M

E)     1.50 ×10- 6   M

 

 

               

 

 

19.  

2                           sp                                                                                                                                                 2

An unknown salt, M Z, has a K of 3.3 ×10- 9 . Calculate the solubility in mol/L of M Z.

A)   2.9 ×10- 5 M

B)     5.7 ×10- 5  M

C)     9.4 ×10- 4  M

D)   3.7 ×10- 4  M

E)     none of the above

 

 

 

 

 

20.  

3                           sp                                                                                                                                                    3

An unknown salt, M Z, has a K of 1.2 ×10- 17 . Calculate the solubility in mol/L of M Z.

A)   2.6 ×10- 5 M

B)     3.5 ×10- 9  M

C)     1.4 ×10- 6  M

D)   2.2 ×10- 6  M

E)     none of the above

 

 

               

 

 

21. Calculate the concentration of Al³⁺ in a saturated aqueous solution of Al(OH)3 (Ksp = 2.2 ´ 10^–32).

A)  7.0 ×10- 9

B)     2.0 ×10- 34

C)     1.2 ×10- 8

D)  8.1 ×10- 34

E)     5.3 ×10- 9

 

                                              

 

 

22. In a solution prepared by adding excess PbI2 (Ksp = 1.44 ´ 10^–8) to water, the [I^–] at equilibrium is:

A)    1.53 ×10- 3 mol/L

B)     7.20 ×10- 9   mol/L

C)     1.20 ×10- 4 mol/L

D)    9.33 ×10- 26 mol/L

E)     3.07 ×10- 3   mol/L

 

 

                                              

 

 

23. The solubility of silver phosphate, Ag3PO4, at 25°C is 1.55 ´ 10^–5 mol/L. Determine the concentration of the Ag⁺ ion in a saturated solution.

A)    1.55 ×10- 5 M

B)     5.17 ×10- 6   M

C)     4.65 ×10- 5   M

D)   1.94 ×105  M

E)     3.72 ×10- 15 M

 

 

 

 

 

24. Which of the following compounds has the lowest solubility in mol/L in water at 25°C? A)   Ag3PO4     Ksp = 1.8 ´ 10^–18

B)     Sn(OH)2     Ksp = 3 ´ 10^–27

C)     CdS     Ksp = 1.0 ´ 10^–28

D)   CaSO4     Ksp = 6.1 ´ 10^–5

E)     Al(OH)3     Ksp = 2 ´ 10^–33

 

 

 

25. Solubility Products (Ksp) BaSO4         1.5 ´ 10^–9

CoS              5.0 ´ 10^–22

PbSO4         1.3 ´ 10^–8

AgBr            5.0 ´ 10^–13

BaCO3         1.6 ´ 10^–9

Which of the following compounds is the most soluble (in moles/liter)?

1. 1. BaSO4
   2. CoS
   3. PbSO4
   4. AgBr
   5. BaCO3

 

 

 

 

 

26. Which of the following compounds has the lowest solubility in mol/L in water?

A)   Al(OH)3     Ksp = 2 ´ 10^–32

B)     CdS     Ksp = 1.0 ´ 10^–28

C)     PbSO4     Ksp = 1.3 ´ 10^–8

D)   Sn(OH)2     Ksp = 3 ´ 10^–27

E)     MgC2O4     Ksp = 8.6 ´ 10^–5

 

                                              

 

27. Which of the following salts shows the lowest solubility in water? (Ksp values: Ag2S = 1.6 ´ 10^–49; Bi2S3 = 1.0 ´ 10^–72; HgS = 1.6 ´ 10^–54; Mg(OH)2 = 8.9 ´ 10^–12; MnS = 2.3 ´ 10^–13)
    1. Bi2S3
    2. Ag2S
    3. MnS
    4. HgS
    5. Mg(OH)2

 

 

28. How many moles of Fe(OH)2 [Ksp = 1.8 ´ 10^–15] will dissolve in 1.0 liter of water buffered at pH = 10.37?

A)   3.3 ×10- 8

B)     2.3 ×10- 4

C)     5.5 ×10- 8

D)  3.1 ×107

E)     7.7 ×10- 12

 

               

 

 

29. The molar solubility of BaCO3 (Ksp = 1.6 ´ 10^–9) in 0.10 M BaCl2 solution is: A) 1.6 ´ 10^–10

B)     4.0 ´ 10^–5

C)     7.4 ´ 10^–4

D) 0.10

E)     none of these

 

 

                                              

 

 

30. The Ksp of AgI is 1.5 ´ 10^–16. Calculate the solubility in mol/L of AgI in a 0.30 M NaI solution.

A)  4.5 ×10- 17

B)     0.30

C)     1.5 ×10- 16

D)  1.2 ×10- 8

E)     5.0 ×10- 16

 

                                              

 

 

31. The molar solubility of AgCl (Ksp = 1.6 ´ 10^–10) in 0.0035 M sodium chloride at 25°C is: A) 0.0035

B)     5.6 ×10- 13

C)     4.6 ×10- 8

D)  1.6 ×10- 10

E)     none of these

 

 

 

 

 

32. The Ksp of PbSO4 is 1.3 ´ 10^–8. Calculate the solubility (in mol/L) of PbSO4 in a 0.0037 M solution of Na2SO4.

A)   4.8 ×10- 11  M

B)     1.2 ×10- 11  M

C)     3.5 ×10- 6  M

D)   1.3 ×10- 8  M

E)     1.9 ×10- 3  M

 

 

 

 

 

33. The Ksp for PbF2 is 4.0 ´ 10^–8. If a 0.040 M NaF solution is saturated with PbF2, what is the [Pb²⁺] in the solution?

A)   1.0 ×10- 6  M

B)     6.4 ×10- 11  M

C)     6.3 ×10- 4  M

D)   2.5 ×10- 5  M

E)     1.6 ×10- 9  M

 

 

                                              

 

 

34. 

    The Ksp of an unknown salt, MZ2, is                . Calculate the solubility (in mol/L) of MZ2 in a 0.0230 M solution of CaZ2.

A)   1.7 ×10- 5  M

B)     1.4 ×10- 7  M

C)     4.1 ×10- 13  M

D)   3.6 ×10- 11  M

E)     9.0 ×10- 12  M

 

 

                                              

 

 

35.  

3  3                                             3                                                                                                                                sp                           3  3

The solubility of La(IO ) in a 0.42 M KIO solution is 5.6 ×10- 12 mol/L. Calculate the K for La(IO ) .

A)   1.1 ×10- 11

B)     7.6 ×10- 11

C)     4.2 ×10- 13

D)   7.4 ×10- 35

E)     none of these

 

 

 

 

 

36. 

    The solubility of an unknown salt, M2Z, in a 0.0768 M CaZ solution is               mol/L. Calculate the Ksp for M2Z.

A)   9.6 ×10- 20

B)     2.4 ×10- 20

C)     1.7 ×10- 12

D)   7.0 ×10- 28

E)     none of these

 

 

               

 

37.  

4

Chromate ion is added to a saturated solution of Ag2CrO4 to reach 0.78 M CrO ^2–. Calculate the final concentration of silver ion at equilibrium (Ksp for Ag2CrO4 is 9.0 ´ 10^–12).

A)   1.7 ×10- 6 M

B)     3.4 ×10- 6 M

C)     4.8 ×10- 6  M

D)   5.8 ×10- 12  M

E)     2.4 ×10- 6  M

 

 

                                              

 

 

38. Calculate the solubility of Ag2CrO4 (Ksp = 9.0 ´ 10^–12) in a 0.049 M AgNO3 solution.

A)    1.8 ×10- 10 mol/L

B)     9.2 ×10- 11   mol/L

C)     3.7 ×10- 9   mol/L

D)    1.9 ×10- 9 mol/L

E)     none of these

 

 

 

 

 

39. The solubility of Mg(OH)2 (Ksp = 8.9 ´ 10^–12) in 1.0 L of a solution buffered (with large capacity) at pH 9.73 is:
    1. 2.6 ×108 moles

B)     3.1 ×10- 3   moles

C)     1.7 ×10- 7   moles

D)    5.4 ×10- 5 moles

E)     none of these

 

 

                                              

 

 

40. Calculate the solubility of Ca3(PO4)2 (Ksp = 1.3 ´ 10^–32) in a 0.048 M Ca(NO3)2 solution.

A)    5.4 ×10- 15 mol/L

B)     1.1 ×10- 14   mol/L

C)     2.6 ×10- 16   mol/L

D)    2.9 ×10- 29 mol/L

E)     none of these

 

 

               

 

 

41. Calculate the solubility of Cu(OH)2 in a solution buffered at pH = 7.59. (Ksp = 1.6 ´ 10^–19)

A)   3.9 ×10- 7  M

B)     4.1 ×10- 13  M

C)     1.1 ×10- 6  M

D)   1.5 ×10- 13  M

E)     none of these

 

 

 

42. How many moles of CaF2 will dissolve in 3.0 liters of 0.089 M NaF solution? (Ksp for CaF2 = 4.0 ´ 10^–11)

A)  5.0 ×10- 9

B)     1.5 ×10- 10

C)     1.5 ×10- 8

D)   1.7 ×10- 9

E)     none of these

 

 

 

 

 

43. The solubility in mol/L of M(OH)2 in 0.053 M KOH is 1.0 ´ 10^–5 mol/L. What is the Ksp for M(OH)2?

A)   2.8 ×10- 8

B)     5.3 ×10- 7

C)     2.8 ×10- 3

D)  4.0 ×10- 15

E)     2.3 ×10- 6

 

 

               

 

 

44. The two salts AgX and AgY exhibit very similar solubilities in water. It is known that the salt AgX is much more soluble in acid than is AgY. What can be said about the relative strengths of the acids HX and HY?
    1. Nothing.
    2. HY is stronger than HX.
    3. HX is stronger than HY.
    4. The acids are weak acids and have equal values for Ka.
    5. Both acids are strong.

 

 

                                              

 

 

45. 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 salt is more soluble in acidic solution?
    1. AgX
    2. AgY
    3. They are equally soluble in acidic solution.
    4. Cannot be determined by the information given.
    5. None of these (A-D).

 

 

                                              

 

 

46. The solubility of AgCl in water is          the solubility of AgCl in strong acid at the same temperature.
    1. greater than
    2. less than
    3. about the same as
    4. cannot be determined
    5. much different from

 

 

 

 

47. Which of the following solid salts is more soluble in 1.0 M H⁺ than in pure water?
    1. NaCl
    2. CaCO3
    3. KCl
    4. AgCl
    5. KNO3

 

 

                                              

 

 

48. Which of the following solid salts is more soluble in 1.0 M H⁺ than in pure water?
    1. NaCl
    2. KCl
    3. FePO4
    4. AgCl
    5. KNO3

 

 

 

 

 

49. Given the following Ksp values, which statement about solubility in mol/L in water is correct?

 

	Ksp		Ksp
PbCrO4	2.0 ´ 10–16	Pb(OH)2	1.2 ´ 10–15
Zn(OH)2	4.5 ´ 10–17	MnS	2.3 ´ 10–13

 

1. 1. PbCrO4, Zn(OH)2, and Pb(OH)2 have equal solubilities in water.
   2. PbCrO4 has the lowest solubility in water.
   3. The solubility of MnS in water will not be pH dependent.
   4. MnS has the highest molar solubility in water.
   5. A saturated PbCrO4 solution will have a higher [Pb²⁺] than a saturated Pb(OH)2 solution.

 

                                              

 

 

50. The best explanation for the dissolution of ZnS in dilute HCl is that:
    1. The zinc ion is amphoteric.
    2. The sulfide-ion concentration is decreased by the formation of H2S.
    3. the sulfide-ion concentration is decreased by oxidation to sulfur.
    4. the zinc-ion concentration is decreased by the formation of a chloro complex.
    5. The solubility product of ZnCl2 is less than that of ZnS.

 

 

                                              

 

 

51. What is the best way to ensure complete precipitation of SnS from a saturated H2S solution?
    1. Add more H2S.
    2. Add a strong acid.
    3. Add a weak acid.
    4. Add a strong base.
    5. Add a weak base.

 

 

                                              

 

 

52. The Ksp of Al(OH)3 is 2 ´ 10^–32. At what pH will a 0.5 M Al³⁺ solution begin to show precipitation of Al(OH)3? A) 3.5

B)     10.5

C)     1.0

D)   6.0

E)     3.1

 

 

               

 

 

53.  

4

You have a solution consisting of 0.10 M Cl^– and 0.10 M CrO ^2–. You add 0.10 M silver nitrate dropwise to this solution. Given that the Ksp for Ag2CrO4 is 9.0 ´ 10^–12, and that for AgCl is 1.6 ´ 10^–10, which of the following will precipitate first?

1. 1. silver chloride
   2. silver chromate
   3. silver nitrate
   4. cannot be determined by the information given
   5. none of these

 

 

               

 

 

The following questions refer to the following system: 3.5 ´ 10² mL of 3.2 M Pb(NO3)2 and 2.0 ´ 10² mL of 0.020 M

NaCl are added together. Ksp for the lead chloride is 1.6 ´ 10^–5.

 

54. Determine the ion product. A) 1.1 ´ 10^–4

B)     1.5 ´ 10^–2

C)     7.8 ´ 10^–3

D)   8.1 ´ 10^–4

E)     none of these

 

 

               

 

 

55. Will precipitation occur?
    1. Yes.
    2. No.
    3. Maybe, it depends on the temperature.
    4. Maybe, it depends on the limiting reagent concentration.
    5. None of these.

 

 

               

 

 

56. What is the limiting reagent in the formation of the lead chloride?
    1. Pb²⁺
    2. Cl^–
    3. (NO3)^–
    4. PbCl2
    5. Pb(NO3)2

 

 

                                              

 

 

57. Determine the equilibrium concentration of the chloride ion. A) 3.9 ´ 10^–4

B)     8.0 ´ 10^–6

C)     2.8 ´ 10^–3

D)   6.1 ´ 10^–2

E)     none of these

 

 

 

 

 

58. The Ksp for BaF2 is 2.4 ´ 10^–5. When 10 mL of 0.01 M NaF is mixed with 10 mL of 0.01 M BaNO3, will a precipitate form?
    1. No, because Q is 1 ´ 10^–12 and since it is less than Ksp no precipitate will form.
    2. Yes, because Q is 1 ´ 10^–12 and since it is less than Ksp a precipitate will form.
    3. No, because Q is 1.25 ´ 10^–7 and since it is less than Ksp no precipitate will form.
    4. Yes, because Q is 1.25 ´ 10^–7 and since it is less than Ksp a precipitate will form.
    5. None of the above.

 

 

 

 

 

59. How many moles of Ca(NO3)2 must be added to 1.0 L of a 0.182 M KF solution to begin precipitation of CaF2? For CaF2, Ksp = 4.0 ´ 10^–11.

A)   6.0 ×10- 10

B)     2.2 ×10- 10

C)     1.3 ×10- 12

D)   1.2 ×10- 9

E)     3.5 ×10- 5

 

 

                                              

 

 

60. A 50.0-mL sample of 0.100 M Ca(NO3)2 is mixed with 50.00 mL of 0.200 M NaF. When the system has come to equilibrium, which of the following sets of conditions will hold? The Ksp for CaF2 is 4.0 ´ 10^–11.

 

Moles Solid CaF2

Formed                           [Ca²⁺]                             [F^–]

 

A)    

 

B)     

 

 

C)

 

D)

E)     

 

 

 

 

 

61. The Ksp for Mn(OH)2 is 2.0 ´ 10^–13. At what pH will Mn(OH)2 begin to precipitate from a solution in which the initial concentration of Mn²⁺ is 0.10 M?

A)   6.47

B)     13.3

C)     5.85

D)   7.03

E)     8.15

 

 

                                              

 

62. 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?
    1. CuCl
    2. AgCl
    3. AuCl
    4. All will precipitate at the same time.
    5. Cannot be determined.

 

 

 

 

 

63. A 0.012-mol sample of Na2SO4 is added to 400 mL of each of two solutions. One solution contains 1.5 ´ 10^–3 M

BaCl2; the other contains 1.5 ´ 10^–3 M CaCl2. Given that Ksp for BaSO4 = 1.5 ´ 10^–9 and Ksp for CaSO4 = 6.1 ´ 10^–5:

1. 1. BaSO4 would precipitate but CaSO4 would not.
   2. CaSO4 would precipitate but BaSO4 would not.
   3. Both BaSO4 and CaSO4 would precipitate.
   4. Neither BaSO4 nor CaSO4 would precipitate.
   5. Not enough information is given to determine if precipitation would occur.

 

 

               

 

 

64. If 30 mL of 5.0 ´ 10^–4 M Ca(NO3)2 are added to 70 mL of 2.0 ´ 10^–4 M NaF, will a precipitate occur? (Ksp of CaF2 = 4.0 ´ 10^–11)
    1. No, because the ion product is greater than Ksp.
    2. Yes, because the ion product is less than Ksp.
    3. No, because the ion product is less than Ksp.
    4. Not enough information is given.
    5. Yes, because the ion product is greater than Ksp.

 

 

 

 

 

65. The concentration of Mg²⁺ in seawater is 0.052 M. At what pH will 99% of the Mg²⁺ be precipitated as the hydroxide? [Ksp for Mg(OH)2 = 8.9 ´ 10^–12]

A)   8.35

B)     9.22

C)     6.50

D)   10.12

E)     4.86

 

 

                                              

 

66. A precipitate forms when a solution that is 0.10 M in Cu²⁺, Pb²⁺, and Ni²⁺ is saturated with H2S and adjusted to pH =

1. What sulfides are present in the precipitate?

[H2S] = 0.10 M; for H2S, Ka1 ´ Ka2 = 1.1 ´ 10^–24

Ksp: CuS = 8.5 ´ 10^–45, PbS = 7.0 ´ 10^–29, NiS = 3.0 ´ 10^–21

1. CuS, PbS, and NiS
2. PbS and NiS
3. NiS
4. CuS and PbS
5. CuS

 

 

                                              

 

67. 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                          Ksp

Pb(OH)2                 1.4 ´ 10^–20

Mn(OH)2                2.0 ´ 10^–13

Zn(OH)2                  2.1 ´ 10^–16

 

1. 1. No precipitate will form.
   2. Only Pb(OH)2 will precipitate.
   3. Only Mn(OH)2 will precipitate.
   4. Only Zn(OH)2 and Pb(OH)2 will precipitate.
   5. All three hydroxides will precipitate.

 

 

                                              

 

 

68.  

2                                                                                                           sp                  3

An industrial plant processes its waste water through a sedimentation tank that removes hazardous metals by precipitating them as insoluble carbonate salts. If sodium carbonate is gradually added to the tank, what would be the order of precipitation of the metals, Pb²⁺, Cu²⁺, Hg ²⁺, and Zn²⁺ if each is » 1.0 ´ 10^–4 M? ( K PbCO  = 7.4 ´ 10^–14, Ksp CuCO3 = 1.4 ´ 10^–10, Ksp Hg2CO3 = 8.9 ´ 10^–17, and Ksp ZnCO3 = 1.4 ´ 10^–11)

 

2

A)   Pb²⁺, Hg ²⁺, Zn²⁺, Cu²⁺

 

2

B)     Hg ²⁺, Pb²⁺, Zn²⁺, Cu²⁺

 

2

C)     Cu²⁺, Zn²⁺, Pb²⁺, Hg ²⁺

 

2

D)   Cu²⁺, Zn²⁺, Hg ²⁺, Pb²⁺

E)     All metal ions will precipitate at the same time.

 

 

                                              

 

 

69. A solution contains 0.018 moles 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) 0.0 g
B)     1.7 g
C)     2.6 g
D) 3.3 g
E)     5.0 g

 

 

                                              

 

70. A 100.-mL sample of solution contains 10.0 mmol of Ca²⁺ ion. How many mmol of solid Na2SO4 must be added in order to cause precipitation of 99.9% of the calcium as CaSO4? The Ksp of CaSO4 is 6.1 ´ 10^–5. Assume the volume remains constant.

A)   17.4

B)     10.0

C)     61.0

D)   71.0

E)     6.1

 

 

 

 

71.  

3        sp                                                                         3        sp

What is the maximum concentration of carbonate ions that will precipitate BaCO3 but not MgCO3 from a solution that is 1.9 ×10- 3 M each in Mg²⁺ and Ba²⁺? For MgCO , K = 1.0 ´ 10^–15 and for BaCO , K = 2.6 ´ 10^–9.

A)   5.3 ×10- 13  M

B)     1.4 ×10- 6  M

C)     3.2 ×10- 8  M

D)   5.1 ×10- 5  M

E)     None of these; MgCO3 will always precipitate before BaCO3.

 

 

                                              

 

 

72. What is the maximum concentration of iodide ions that will precipitate AgI but not PbI2 from a solution that is

 

sp                                                                 2        sp

1.5 ×10- 3 M each in Ag⁺ and Pb²⁺? For AgI, K = 1.5 ´ 10^–16 and for PbI , K   = 1.4 ´ 10^–8.

A)   3.1 ×10- 3  M

B)     1.0 ×10- 13  M

C)     9.3 ×10- 6  M

D)   1.2 ×10- 8  M

E)     None of these; PbI2 will always precipitate before AgI.

 

 

               

 

 

73. In the qualitative analysis scheme for metal ions, how are the Analytical Group I cations separated from the other cations?
    1. by addition of HCl, forming insoluble metal chlorides
    2. by addition of H2SO4, forming insoluble metal sulfates
    3. by addition of H2S in acidic solution, forming insoluble metal sulfides
    4. by addition of H2S in basic solution, forming insoluble metal sulfides or hydroxides
    5. by addition of (NH4)2CO3 or (NH4)3PO4, forming insoluble metal carbonates or phosphates

 

 

               

 

74. In the qualitative analysis scheme for metal ions, how are the Analytical Group II cations separated from the cat ions of Analytical Groups III–V?
    1. by addition of HCl, forming insoluble metal chlorides
    2. by addition of H2SO4, forming insoluble metal sulfates
    3. by addition of H2S in acidic solution, forming insoluble metal sulfides
    4. by addition of H2S in basic solution, forming insoluble metal sulfides or hydroxides
    5. by addition of (NH4)2CO3 or (NH4)3PO4, forming insoluble metal carbonates or phosphates

 

 

 

 

 

75. 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?
    1. by addition of HCl, forming insoluble metal chlorides
    2. by addition of H2SO4, forming insoluble metal sulfates
    3. by addition of H2S in acidic solution, forming insoluble metal sulfides
    4. by addition of H2S in basic solution, forming insoluble metal sulfides or hydroxides
    5. by addition of (NH4)2CO3 or (NH4)3PO4, forming insoluble metal carbonates or phosphates

 

 

                                              

 

 

76. When a mixture containing cations of Analytical Groups I–III is treated with H2S in acidic solution, which cations are expected to precipitate?
    1. Analytical Group I only
    2. Analytical Group II only
    3. Analytical Group III only
    4. Analytical Groups I and II
    5. Analytical Groups II and III

 

 

                                              

 

 

77. In the classic scheme for qualitative analysis, the cations of Analytical Group IV are precipitated as phosphates or carbonates. Analytical Group IV consists of
    1. alkali metals
    2. alkaline earth elements
    3. the halogens
    4. transition metals having +2 ions
    5. none of these

 

 

                                              

 

 

78. 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 (i.e., did not precipitate)?
    1. Ag⁺ only
    2. Na⁺, Hg²⁺, Al³⁺
    3. Ag⁺ and Hg²⁺
    4. Na⁺, Al³⁺, and Mn²⁺
    5. Na⁺ only

 

 

                                              

 

 

79. Which of the following solid salts should be more soluble in 1.0 M NH3 than in water?
    1. Na2CO3
    2. KCl
    3. AgBr
    4. KNO3
    5. none of these

 

 

 

 

80.  

3 2

The overall Kf for the complex ion Ag(NH ) ⁺ is 1.7 ´ 10⁷. The Ksp for AgI is 1.5 ´ 10^–16. What is the molar solubility of AgI in a solution that is 2.0 M in NH3?

A)   1.5 ´ 10^–9

B)     1.3 ´ 10^–3

C)     1.0 ´ 10^–4

D) 5.8 ´ 10^–12

E)     8.4 ´ 10^–5

 

 

 

 

81.  

3 2

The Kf for the complex ion Ag(NH ) ⁺ is 1.7 ´ 10⁷. The Ksp for AgCl is 1.6 ´ 10^–10. Calculate the molar solubility of AgCl in 1.0 M NH3.

A)   5.2 ´ 10^–2

B)     4.7 ´ 10^–2

C)     2.9 ´ 10^–3

D)   1.3 ´ 10^–5

E)     1.7 ´ 10^–10

 

 

                                              

 

 

82. Given the following values of equilibrium constants:

 

2

3  4                                                                         3

Cu(OH) (s)         Cu²⁺(aq) + 2OH^–(aq)                       Ksp = 1.60 ´ 10–19 Cu(NH ) ²⁺(aq)         Cu²⁺(aq) + 4NH (aq)                 K = 1.0 ´ 10–13

What is the value of the equilibrium constant for the following reaction?

 

 

3 4

Cu(OH)2(s) + 4NH3(aq)      Cu(NH ) ²⁺(aq) + 2OH^–(aq)

A)  1.60 ×10- 19

B)     1.6 ×10- 32

C)     1.6 ×10- 6

D)  6.25 ×1018

E)     1.0 ×1013

 

 

 

 

 

83.  

3 2

The concentration of Ag(NH ) ⁺ at equilibrium is:

1. 1. 2.0 M

B)     0.40 M

C)     0.20 M

D) 1.0 ´ 10^–3 M

E)     none of these

 

 

 

 

84. The concentration of Ag⁺ at equilibrium is:
    1. 2.0 M

B)     1.2 ´ 10^–8 M

C)     4.5 ´ 10^–9 M

4. 1.6 M
5. none of these

 

 

 

 

 

The following questions refer to the following system: 500.0 mL of 0.020 M Mn(NO3)2 are mixed with 1.0 L of 1.0 M Na2C2O4. The oxalate ion, C2O4, acts as a ligand to form a complex ion with the Mn²⁺ ion with a coordination number of two.

 

2     4                                2     4

Mn²⁺ + C O ^2–         MnC O                                               K1 = 7.9 ´ 103

 

2    4  2                                  2     4           2    4

[Mn(C O ) ]^2–         MnC O + C O ^2–                               K2 = 1.26 ´ 10–2

 

85. What is the equilibrium constant for the following formation?

 

 

4

Mn²⁺ + 2C2O ^2–       [Mn(C2O4)2]^2– A) 1.0

B)     3.7 ´ 10²

C)     2.1 ´ 10^–1

D) 6.3 ´ 10⁵

E)     none of these

 

 

                                              

 

 

86. Find the equilibrium concentration of the [Mn(C2O4)2]^2– ion. A) 9.2 ´ 10^–5 M

B)     0.01 M

C)     2.5 ´ 10^–8 M

D)   1.3 ´ 10^–4 M

E)     6.7 ´ 10^–3 M

 

 

                                              

 

 

87. Find the equilibrium concentration of Mn(C2O4) in the system. A) 9.2 ´ 10^–5 M

B)     0.01 M

C)     2.5 ´ 10^–8 M

D)   1.3 ´ 10^–4 M

E)     6.7 ´ 10^–3 M

 

 

                                              

 

 

88. Find the equilibrium concentration of the Mn²⁺ ion. A) 9.2 ´ 10^–5 M

B)     0.01 M

C)     2.5 ´ 10^–8 M

D)   1.3 ´ 10^–4 M

E)     6.7 ´ 10^–3 M

 

 

 

 

 

89. Silver acetate, AgC2H3O2, is a sparingly soluble salt with Ksp = 1.9 ´ 10^–3. Consider a saturated solution in equilibrium with the solid salt. Compare the effects on the solubility of adding to the solution either the acid HNO3 or the base NH3.
    1. Either substance would decrease the solubility.
    2. NH3 would increase the solubility, but HNO3 would decrease it.
    3. NH3 would increase the solubility, but HNO3 would have virtually no effect.
    4. Either substance would increase the solubility.
    5. NH3 would decrease the solubility, but HNO3 would increase it.

 

 

                                              

 

90.  

3 4

3 4

Calculate the molar concentration of uncomplexed Zn²⁺ in a solution that contains 0.20 mole of Zn(NH ) ²⁺ per liter and 0.0116 M NH3 at equilibrium. The overall Kf for Zn(NH ) ²⁺ is 3.8 ´ 10⁹.

A)   2.9 ´ 10^–3 M

B)     8.8 ´ 10^–3 M

C)     6.7 ´ 10^–4 M

D) 2.0 ´ 10^–13 M

E)     none of these

 

 

               

 

91.  

3                                 3

The cation M²⁺ reacts with NH3 to form a series of complex ions as follows: M²⁺ + NH                                                                   M(NH )²⁺                             K1 = 102

 

3                       3                                 3 2

M(NH )²⁺ + NH          M(NH ) ²⁺                                           K2 = 103

 

3  2                     3                                 3 3

M(NH ) ²⁺ + NH           M(NH ) ²⁺                                          K3 = 102

A 1.0 ´ 10^–3 mol sample of M(NO3)2 is added to 1.0 L of 15.0 M NH3 (Kb = 1.8 ´ 10^–5). Choose the dominant species in this solution.

1. 1. M²⁺
   2. M(NH3)²⁺
   3.  

3 2

M(NH ) ²⁺

1. 4.  

3 3

M(NH ) ²⁺

1. 5. M(NO3)2

 

 

                                              

 

 

92.  

3 3

What is the molar solubility of lead(II) chromate in 0.055 M Na2S2O3? For PbCrO4, Ksp = 2.0 ´ 10^–16; for Pb(S2O ) ^4–,

Kf = 2.2 ´ 10⁶.

A)   2.7 ×10- 7  M

B)     4.9 ×10- 6  M

C)     4.4 ×10- 10  M

D)   6.1 ×102  M

E)     1.7 ×10- 4  M

 

 

               

 

93. Consider the following three complex ions of Ag⁺ and their formation constants, Kf. Ag(NH3)2+                Kf = 1.7 ´ 10⁷

Ag(CN)2–     Kf = 5.6 ´ 10¹⁸

AgBr2–            Kf = 1.0 ´ 10¹¹

Which of the following responses are true?

1. Ag(NH3)2+ is more stable than Ag(CN)2–.
2. Adding a strong acid (HNO3) to a solution that is 0.010 M in Ag(NH3)2+ would tend to dissociate the complex ion.
3. Adding a strong acid (HNO3) to a solution that is 0.010 M in AgBr2– would tend to dissociate the complex ion.
4. To dissolve AgI add either NaCN or HCN, fewer moles of NaCN would be required.

1. 1 and 2
2. 1 and 3
3. 1 and 4
4. 2 and 4
5. 2 and 3

                                              

 

94.  

3 6

What is the concentration of Ni²⁺(aq) ion in a 0.045 M Ni(NO3)2 solution that is also 1.0 M NH3? [Kf for Ni(NH ) ²⁺ = 5.5 ´ 10⁸]

A)   5.4 ×10- 10  M

B)     1.1 ×10- 10  M

C)     8.2 ×10- 11  M

D)   4.5 ×10- 2  M

E)     none of these

 

 

               

 

 

95.  

3 4

What is the concentration of the Cd²⁺(aq) ion in a 0.030 M Cd(NO3)2 solution that is also 1.0 M NH3? At this temperature, Kf for Cd(NH ) ²⁺ = 1.0 ´ 10⁷.

A)   3.0 ×10- 9  M

B)     5.0 ×10- 9  M

C)     3.0 ×10- 30  M

D)   1.0 ×10- 7  M

E)     none of these

 

 

                                              

 

 

96. The correct mathematical expression for finding the molar solubility (s) of silver chloride is:
    1. s² = Ksp
    2. 2s³ = Ksp
    3. 108s⁵ = Ksp
    4. 4s³ = Ksp
    5. 27s⁴ = Ksp

 

               

 

 

97. The correct mathematical expression for finding the molar solubility (s) of barium chloride is:bacl2
    1. s² = Ksp
    2. 2s³ = Ksp
    3. 108s⁵ = Ksp
    4. 4s³ = Ksp
    5. 27s⁴ = Ksp

 

                                              

 

 

98. The correct mathematical expression for finding the molar solubility (s) of iron(III) hydroxide is:Feoh3
    1. s² = Ksp
    2. 2s³ = Ksp
    3. 108s⁵ = Ksp
    4. 4s³ = Ksp
    5. 27s⁴ = Ksp

                                              

 

 

99. The correct mathematical expression for finding the molar solubility (s) of silver(I)phosphide is:ag3p
    1. s² = Ksp
    2. 2s³ = Ksp
    3. 108s⁵ = Ksp
    4. 4s³ = Ksp
    5. 27s⁴ = Ksp

 

                                              

 

 

100. The correct mathematical expression for finding the molar solubility (s) of silver(I)sulfide is:ag2s
     1. s² = Ksp
     2. 2s³ = Ksp
     3. 108s⁵ = Ksp
     4. 4s³ = Ksp
     5. 27s⁴ = Ksp

 

                                              

 

 

101. The correct mathematical expression for finding the molar solubility (s) of aluminum sulfide is:al2s3
     1. s² = Ksp
     2. 2s³ = Ksp
     3. 108s⁵ = Ksp
     4. 4s³ = Ksp
     5. 27s⁴ = Ksp

 

 

 

 

102. The correct mathematical expression for finding the molar solubility (s) of calcium phosphate is:ca3p2
     1. s² = Ksp
     2. 2s³ = Ksp
     3. 108s⁵ = Ksp
     4. 4s³ = Ksp
     5. 27s⁴ = Ksp

 

 

 

 

103. Given that the Ksp for calcium fluoride [CaF2] is 3.2 x 10^-15, which of the following describes a solution that is 2.00 x 10^-5 M NaF and 2.00 x 10^-5 M Ca(NO3)2?
     1. Q = 4 x 10^-10 and there will be a precipitate formed
     2. Q = 8 x 10^-10 and there will be a precipitate formed
     3. Q = 8 x 10^-15 and there will be no precipitate formed
     4. Q = 1.3 x 10^-13 and there will be a precipitate formed
     5. Q = 8 x 10^-15 and there will be a precipitate formed

 

 

                                              

 

 

104. A solution is 2.00 x 10^-3 M Ba(NO3)2 and 0.0500 M KF. Given that the Ksp of barium fluoride is 1.5 x 10^-6,
     1. Qsp = 1 x 10^-4 so a precipitate will be observed.
     2. Qsp = 2 x 10^-4 so a precipitate will be observed.