General ChemistryPrinciples & Modern Applications

9th EditionPetrucci/Harwood/Herring/Madura

Chapter 18

Solubility and Complex Ion Solubility

Dr. Travis D. Fridgen

Memorial University of Newfoundland

© 2007 Pearson Education

Which of the following compounds is expected to not dissolve to a great extent in water? (ie. remember solubility rules).

1. NaOH

2. CaCl2

3. K3PO4

5. AgNO3

4. Ca3(PO4)2

Which of the following compounds is expected to not dissolve to a great extent in water? (ie. remember solubility rules).

1. NaOH

2. CaCl2

3. K3PO4

5. AgNO3

4. Ca3(PO4)2

Which of the following lead (II) salts will dissolve to the greatest extent in water? (No calculators)

1. PbSO4, Ksp = 1.7x10-8

2. PbI2, Ksp = 6.5x10-9

3. PbCrO4, Ksp = 1.8x10-14

4. PbS, Ksp = 2.5x10-27

5. Pb3(AsO4)2, Ksp = 4.0x10-36

Which of the following lead (II) salts will dissolve to the greatest extent in water? (No calculators)

1. PbSO4, Ksp = 1.7x10-8

2. PbI2, Ksp = 6.5x10-9

3. PbCrO4, Ksp = 1.8x10-14

4. PbS, Ksp = 2.5x10-27

5. Pb3(AsO4)2, Ksp = 4.0x10-36

Gallium(III) hydroxide, Ga(OH)3, is a sparingly soluble ionic compound with a Ksp of about 1x10-35. What is the approximate total concentration of ions in a saturated solution of Fe(OH)3? (No calculators, do a back of the envelope calculation).

1. 1x10-8 M

5. 2x10-37 M

2. 1x10-9 M

3. 4x10-9 M

4. 4x10-36 M

Gallium(III) hydroxide, Ga(OH)3, is a sparingly soluble ionic compound with a Ksp of about 1x10-35. What is the approximate total concentration of ions in a saturated solution of Fe(OH)3? (No calculators, do a back of the envelope calculation).

1. 1x10-8 M

5. 2x10-37 M

2. 1x10-9 M

3. 4x10-9 M

4. 4x10-36 M

A saturated solution of which of the following hydroxides has the lowest pH?

4. Al(OH)3, Ksp = 3.0x10-34

2. Cd(OH)2, Ksp = 7.2x10-15

3. CuOH, Ksp = 2.1x10-20

5. Fe(OH)3, Ksp = 2.8x10-39

1. NaOH

A saturated solution of which of the following hydroxides has the lowest pH?

4. Al(OH)3, Ksp = 3.0x10-34

2. Cd(OH)2, Ksp = 7.2x10-15

3. CuOH, Ksp = 2.1x10-20

5. Fe(OH)3, Ksp = 2.8x10-39

1. NaOH

Saturated solutions of which of the following ionic compounds have the highest boiling point?

1. Cd(OH)2 (Ksp = 5.9x10-15)

2. Zn(OH)2 (Ksp = 1.1x10-17)

3. Mg3(PO4)2 (Ksp = 1.0x10-25)

4. AgCN (Ksp = 7.2x10-11)

5. AgI (Ksp = 8.5x10-17)

Saturated solutions of which of the following ionic compounds have the highest boiling point?

1. Cd(OH)2 (Ksp = 5.9x10-15)

2. Zn(OH)2 (Ksp = 1.1x10-17)

3. Mg3(PO4)2 (Ksp = 1.0x10-25)

4. AgCN (Ksp = 7.2x10-11)

5. AgI (Ksp = 8.5x10-17)

Many dentists recommend fluoride treatment which replaces the hydroxyapatite, Ca5(PO4)3OH, in tooth enamel with fluoroapatite, Ca5(PO4)3F. This decreases the solubility of tooth enamel by more than two orders of magnitude from 5.2x10-5 M to 1.2x10-7 M. What is the Ksp for fluoroapatite?

1. 6.3x10-37

5. 2.3x10-65

4. 5.2x10-63

2. 1.2x10-60

3. 7.7x10-62

Many dentists recommend fluoride treatment which replaces the hydroxyapatite, Ca5(PO4)3OH, in tooth enamel with fluoroapatite, Ca5(PO4)3F. This decreases the solubility of tooth enamel by more than two orders of magnitude from 5.2x10-5 M to 1.2x10-7 M. What is the Ksp for fluoroapatite?

1. 6.3x10-37

5. 2.3x10-65

4. 5.2x10-63

2. 1.2x10-60

3. 7.7x10-62

2+31. Pb (aq) + 3OH (aq) Pb(OH) (aq) K = 0.4

2+32. Pb (aq) + 3OH (aq) Pb(OH) (aq) K = 40

2 34. Pb(OH) (s) + OH (aq) Pb(OH) (aq) K = 4

292 35. Pb(OH) (s) + OH (aq) Pb(OH) (aq) K = 4 10

3 2 3 33. Pb(NO ) (s) + 3OH (aq) Pb(OH) (aq) + 3NO (aq) K = 0.4

A solution of lead(II) nitrate was made slightly basic and was found to precipitate out lead(II) hydroxide. After making the solution very basic the white precipitate disappeared and it was determined that the dominant species in solution (besides hydroxide) was Pb(OH)3

-. The Ksp of Pb(OH)2 and the formation constant of Pb(OH)3

- are 1x10-15 and 4x1014, respectively. Which of the following is correct for the net ionic equation for the reaction which takes place?

2+31. Pb (aq) + 3OH (aq) Pb(OH) (aq) K = 0.4

2+32. Pb (aq) + 3OH (aq) Pb(OH) (aq) K = 40

2 34. Pb(OH) (s) + OH (aq) Pb(OH) (aq) K = 4

292 35. Pb(OH) (s) + OH (aq) Pb(OH) (aq) K = 4 10

3 2 3 33. Pb(NO ) (s) + 3OH (aq) Pb(OH) (aq) + 3NO (aq) K = 0.4

A solution of lead(II) nitrate was made slightly basic and was found to precipitate out lead(II) hydroxide. After making the solution very basic the white precipitate disappeared and it was determined that the dominant species in solution (besides hydroxide) was Pb(OH)3

-. The Ksp of Pb(OH)2 and the formation constant of Pb(OH)3

- are 1x10-15 and 4x1014, respectively. Which of the following is correct for the net ionic equation for the reaction which takes place?

To improve the quality of X-ray photos used in the diagnosis of intestinal disorders the patient drinks an aqueous suspension of BaSO4 before having the X-ray. However, BaSO4 is slightly soluble (Ksp = 1.1x10-10 and Ba2+ is toxic. Which of the following compounds would be the best to add to the suspension in order to make it less concentrated in Ba2+ and less toxic to the patient?

1. NaNO3

2. Ba(NO3)2

3. NaCl

4. Na2SO4

5. H2SO4

To improve the quality of X-ray photos used in the diagnosis of intestinal disorders the patient drinks an aqueous suspension of BaSO4 before having the X-ray. However, BaSO4 is slightly soluble (Ksp = 1.1x10-10 and Ba2+ is toxic. Which of the following compounds would be the best to add to the suspension in order to make it less concentrated in Ba2+ and less toxic to the patient?

1. NaNO3

2. Ba(NO3)2

3. NaCl

4. Na2SO4

5. H2SO4

Magnesium hydroxide (Mg(OH)2) is only sparingly soluble in water.

2+2

-11sp

Mg(OH) (s) Mg (aq) + 2OH (aq)

K = 1.1 10

Which of the following will increase the solubility of Mg(OH)2?

1. Add Mg(NO3)2

2. Add KOH

3. Add CaCl2

4. Add HCl

5. Add NH3

Magnesium hydroxide (Mg(OH)2) is only sparingly soluble in water.

2+2

-11sp

Mg(OH) (s) Mg (aq) + 2OH (aq)

K = 1.1 10

Which of the following will increase the solubility of Mg(OH)2?

1. Add Mg(NO3)2

2. Add KOH

3. Add CaCl2

4. Add HCl

5. Add NH3

Which of the following substances would be more soluble if the pH of the solution decreases?

1. All are more soluble at lower pH.

2. None become more soluble at lower pH.

3. i) and iii).

4. i), iv), and v).

5. i), ii), iv), and v).

i)i) AgAg33POPO44

ii)ii) HgHg22ClCl22

iii)iii) PbIPbI22

iv)iv) Cd(OH)Cd(OH)22

v)v) PbSPbS

Which of the following substances would be more soluble if the pH of the solution decreases?

1. All are more soluble at lower pH.

2. None become more soluble at lower pH.

3. i) and iii).

4. i), iv), and v).

5. i), ii), iv), and v).

i)i) AgAg33POPO44

ii)ii) HgHg22ClCl22

iii)iii) PbIPbI22

iv)iv) Cd(OH)Cd(OH)22

v)v) PbSPbS

One mole (~107 g) of Fe(OH)3 was dumped into 1 L of water. The Ksp of Fe(OH)3 is 4.0x10-38 and obviously only a small fraction dissolved. After one mole of KCN was dumped into the mixture all of the Fe(OH)3 dissolved.

3+ 3 416 spFe + 6CN Fe(CN) K = 9.1 10

1. True

2. False

3. Not enough information to determinea) b)

One mole (~107 g) of Fe(OH)3 was dumped into 1 L of water. The Ksp of Fe(OH)3 is 4.0x10-38 and obviously only a small fraction dissolved. After one mole of KCN was dumped into the mixture all of the Fe(OH)3 dissolved.

3+ 3 416 spFe + 6CN Fe(CN) K = 9.1 10

1. True

2. False

3. Not enough information to determinea) b)

To an aqueous solution containing NaCl a solution containing AgNO3 was added. To the resulting solution, an ammonia (NH3) solution was added. Finally a strong nitric acid solution was added. Which of the following is best representative of what one would observe for this experiment?

1. 2.

3. 4.

5.

To an aqueous solution containing NaCl a solution containing AgNO3 was added. To the resulting solution, an ammonia (NH3) solution was added. Finally a strong nitric acid solution was added. Which of the following is best representative of what one would observe for this experiment?

1. 2.

3. 4.

5.

A series of ionic compounds, A, B, and C, were added to a solution of AgNO3. The qualitative results are as in the diagram to the right. Compounds, A, B, and C, respectively, are:

precipitate

A B C

1. NaNO3, HBr, NaCl

2. NaCl, NH3, CH3COONa

3. NaBr, NH3, HNO3

4. NaCl, NH4Cl, NaNO3

A series of ionic compounds, A, B, and C, were added to a solution of AgNO3. The qualitative results are as in the diagram to the right. Compounds, A, B, and C, respectively, are:

precipitate

A B C

1. NaNO3, HBr, NaCl

2. NaCl, NH3, CH3COONa

3. NaBr, NH3, HNO3

4. NaCl, NH4Cl, NaNO3