Calculate the solubility of solid Pb3(PO4)2 (Ksp 5 1 3

Copper(I) bromide has a measured solubility of 2.0 3 1024 mol/L at 258C. Calculate its Ksp value.

Calculate the Ksp value for bismuth sulfide (Bi2S3), which has a solubility of 1.0 3 10215 mol/L at 258C.

The Ksp value for copper(II) iodate, Cu(IO3)2, is 1.4 3 1027 at 258C. Calculate its solubility at 258C.

What if all you know about two salts is that the value of Ksp for salt A is greater than that of salt B? Why can we not compare relative solubilities of the salts? Use numbers to show how salt A could be more soluble than salt B, and how salt B could be more soluble than salt A.

Calculate the solubility of solid CaF2 (Ksp 5 4.0 3 10211) in a 0.025-M NaF solution.

You and a friend are studying for a chemistry exam. What if your friend tells you that since acids are very reactive, all salts are more soluble in aqueous solutions of acids than in water? How would you explain to your friend that this is not true? Use a specific example to defend your answer.

A solution is prepared by adding 750.0 mL of 4.00 3 1023 M Ce(NO3)3 to 300.0 mL of 2.00 3 1022 M KIO3. Will Ce(IO3)3 (Ksp 5 1.9 3 10210) precipitate from this solution?

A solution is prepared by mixing 150.0 mL of 1.00 3 1022 M Mg(NO3)2 and 250.0 mL of 1.00 3 1021 M NaF. Calculate the concentrations of Mg21 and F2 at equilibrium with solid MgF2 (Ksp 5 6.4 3 1029 ).

A solution contains 1.0 3 1024 M Cu1 and 2.0 3 1023 M Pb21. If a source of I2 is added gradually to this solution, will PbI2 (Ksp 5 1.4 3 1028 ) or CuI (Ksp 5 5.3 3 10212) precipitate first? Specify the concentration of I2 necessary to begin precipitation of each salt.

Calculate the concentrations of Ag1, Ag(S2O3)2, and Ag(S2O3)2 32 in a solution prepared by mixing 150.0 mL of 1.00 3 1023 M AgNO3 with 200.0 mL of 5.00 M Na2S2O3. The stepwise formation equilibria are Ag1 1 S2O3 22mAg1S2O32 2 K1 5 7.4 3 108 Ag1S2O32 2 1 S2O3 22mAg1S2O32 2 32 K2 5 3.9 3 104

Calculate the concentrations of Ag1, Ag(S2O3)2, and Ag(S2O3)2 32 in a solution prepared by mixing 150.0 mL of 1.00 3 1023 M AgNO3 with 200.0 mL of 5.00 M Na2S2O3. The stepwise formation equilibria are Ag1 1 S2O3 22mAg1S2O32 2 K1 5 7.4 3 108 Ag1S2O32 2 1 S2O3 22mAg1S2O32 2 32 K2 5 3.9 3 104

Under what circumstances can you compare the relative solubilities of two salts directly by comparing the values of their solubility products? When can relative solubilities not be compared based on Ksp values?

What is a common ion and how does its presence affect the solubility?

List some salts whose solubility increases as the pH becomes more acidic. What is true about the anions in these salts? List some salts whose solubility remains unaffected by the solution pH. What is true about the anions in these salts?

What is the difference between the ion product, Q, and the solubility product, Ksp? What happens when Q . Ksp? Q , Ksp? Q 5 Ksp?

Mixtures of metal ions in aqueous solution can sometimes be separated by selective precipitation. What is selective precipitation? If a solution contained 0.10 M Mg21, 0.10 M Ca21, and 0.10 M Ba21, how could addition of NaF be used to separate the cations out of solutionthat is, what would precipitate first, then second, then third? How could addition of K3PO4 be used to separate out the cations in a solution that is 1.0 M Ag1, 1.0 M Pb21, and 1.0 M Sr21?

Figure 16.2 summarizes the classic method for separating a mixture of common cations by selective precipitation. Explain the chemistry involved with each of the four steps in the diagram

What is a complex ion? The stepwise formation constants for the complex ion Cu(NH3)4 21 are K1 < 1 3 103 , K2 < 1 3 104 , K3 < 1 3 103 , and K4 < 1 3 103 . Write the reactions that refer to each of these formation constants. Given that the values of the formation constants are large, what can you deduce about the equilibrium concentration of Cu(NH3)4 21 versus the equilibrium concentration of Cu21?

When 5 M ammonia is added to a solution containing Cu(OH)2(s), the precipitate will eventually dissolve in solution. Why? If 5 M HNO3 is then added, the Cu(OH)2 precipitate re-forms. Why? In general, what effect does the ability of a cation to form a complex ion have on the solubility of salts containing that cation?

Figure 16.3 outlines the classic scheme for separating a mixture of insoluble chloride salts from one another. Explain the chemistry involved in the various steps of the figure.

Which of the following will affect the total amount of solute that can dissolve in a given amount of solvent? a. The solution is stirred. b. The solute is ground to fine particles before dissolving. c. The temperature changes

Devise as many ways as you can to experimentally determine the Ksp value of a solid. Explain why each of these would work.

You are browsing through the Handbook of Hypothetical Chemistry when you come across a solid that is reported to have a Ksp value of zero in water at 258C. What does this mean?

A friend tells you: The constant Ksp of a salt is called the solubility product constant and is calculated from the concentrations of ions in the solution. Thus, if salt A dissolves to a greater extent than salt B, salt A must have a higher Ksp than salt B. Do you agree with your friend? Explain

Explain the following phenomenon: You have a test tube with an aqueous solution of silver nitrate as shown in test tube 1 on the following page. A few drops of aqueous sodium chromate solution was added with the end result shown in test tube 2. A few drops of aqueous sodium chloride solution was then added with the end result shown in test tube 3. 1 CrO4 2 2 3 Cl Use the Ksp values in the book to support your explanation, and include the balanced equations. Also, list the ions that are present in solution in each test tube.

What happens to the Ksp value of a solid as the temperature of the solution changes? Consider both increasing and decreasing temperatures, and explain your answer

Which is more likely to dissolve in an acidic solution, silver sulfide or silver chloride? Why?

For which of the following is the Ksp value of the ionic compound the largest? The smallest? Explain your answer.

Ag2S(s) has a larger molar solubility than CuS even though Ag2S has the smaller Ksp value. Explain how this is possible.

Solubility is an equilibrium position, whereas Ksp is an equilibrium constant. Explain the difference.

The salts in Table 16.1, with the possible exception of the hydroxide salts, generally have one of the following mathematical relationships between the Ksp value and the molar solubility s. i. Ksp 5 s2 iii. Ksp 5 27s4 ii. Ksp 5 4s3 iv. Ksp 5 108s5 For each mathematical relationship, give an example of a salt in Table 16.1 that exhibits that relationship

When Na3PO4(aq) is added to a solution containing a metal ion and a precipitate forms, the precipitate generally could be one of two possibilities. What are the two possibilities?

The common ion effect for ionic solids (salts) is to significantly decrease the solubility of the ionic compound in water. Explain the common ion effect.

Sulfide precipitates are generally grouped as sulfides insoluble in acidic solution and sulfides insoluble in basic solution. Explain why there is a difference between the two groups of sulfide precipitates.

List some ways one can increase the solubility of a salt in water.

The stepwise formation constants for a complex ion usually have values much greater than 1. What is the significance of this?

Silver chloride dissolves readily in 2 M NH3 but is quite insoluble in 2 M NH4NO3. Explain

If a solution contains either Pb21(aq) or Ag1(aq), how can temperature be manipulated to help identify the ion in solution?

Write balanced equations for the dissolution reactions and the corresponding solubility product expressions for each of the following solids. a. AgC2H3O2 b. Al(OH)3 c. Ca3(PO4)2

Write balanced equations for the dissolution reactions and the corresponding solubility product expressions for each of the following solids. a. Ag2CO3 b. Ce(IO3)3 c. BaF2

Use the following data to calculate the Ksp value for each solid. a. The solubility of CaC2O4 is 4.8 3 1025 mol/L. b. The solubility of BiI3 is 1.32 3 1025 mol/L.

Use the following data to calculate the Ksp value for each solid. a. The solubility of Pb3(PO4)2 is 6.2 3 10212 mol/L. b. The solubility of Li2CO3 is 7.4 3 1022 mol/L.

Approximately 0.14 g nickel(II) hydroxide, Ni(OH)2(s), dissolves per liter of water at 208C. Calculate Ksp for Ni(OH)2(s) at this temperature

The solubility of the ionic compound M2X3, having a molar mass of 288 g/mol, is 3.60 3 1027 g/L. Calculate the Ksp of the compound.

The concentration of Pb21 in a solution saturated with PbBr2(s) is 2.14 3 1022 M. Calculate Ksp for PbBr2.

The concentration of Ag1 in a solution saturated with Ag2C2O4(s) is 2.2 3 1024 M. Calculate Ksp for Ag2C2O4.

Calculate the solubility of each of the following compounds in moles per liter. Ignore any acidbase properties. a. Ag3PO4, Ksp 5 1.8 3 10218 b. CaCO3, Ksp 5 8.7 3 1029 c. Hg2Cl2, Ksp 5 1.1 3 10218 (Hg2 21 is the cation in solution.)

Calculate the solubility of each of the following compounds in moles per liter. Ignore any acidbase properties. a. PbI2, Ksp 5 1.4 3 1028 b. CdCO3, Ksp 5 5.2 3 10212 c. Sr3(PO4)2, Ksp 5 1 3 10231

Cream of tartar, a common ingredient in cooking, is the common name for potassium bitartrate (abbreviated KBT, molar mass 5 188.2 g/mol). Historically, KBT was a crystalline solid that formed on the casks of wine barrels during the fermentation process. Calculate the maximum mass of KBT that can dissolve in 250.0 mL of solution to make a saturated solution. The Ksp value for KBT is 3.8 3 1024

Barium sulfate is a contrast agent for X-ray scans that are most often associated with the gastrointestinal tract. Calculate the mass of BaSO4 that can dissolve in 100.0 mL of solution. The Ksp value for BaSO4 is 1.5 3 1029 .

Calculate the molar solubility of Mg(OH)2, Ksp 5 8.9 3 10212

Calculate the molar solubility of Cd(OH)2, Ksp 5 5.9 3 10211.

Calculate the molar solubility of Al(OH)3, Ksp 5 2 3 10232.

Calculate the molar solubility of Co(OH)3, Ksp 5 2.5 3 10243.

For each of the following pairs of solids, determine which solid has the smallest molar solubility. a. CaF2(s), Ksp 5 4.0 3 10211, or BaF2(s), Ksp 5 2.4 3 1025 b. Ca3(PO4)2(s), Ksp 5 1.3 3 10232, or FePO4(s), Ksp 5 1.0 3 10222

For each of the following pairs of solids, determine which solid has the smallest molar solubility. a. FeC2O4, Ksp 5 2.1 3 1027 , or Cu(IO4)2, Ksp 5 1.4 3 1027 b. Ag2CO3, Ksp 5 8.1 3 10212, or Mn(OH)2, Ksp 5 2 3 10213

Calculate the solubility (in moles per liter) of Fe(OH)3 (Ksp 5 4 3 10238) in each of the following. a. water b. a solution buffered at pH 5 5.0 c. a solution buffered at pH 5 11.0

Calculate the solubility of Co(OH)2(s) (Ksp 5 2.5 3 10216) in a buffered solution with a pH of 11.00.

The Ksp for silver sulfate (Ag2SO4) is 1.2 3 1025 . Calculate the solubility of silver sulfate in each of the following. a. water b. 0.10 M AgNO3 c. 0.20 M K2SO4

The Ksp for lead iodide (PbI2) is 1.4 3 1028 . Calculate the solubility of lead iodide in each of the following. a. water b. 0.10 M Pb(NO3)2 c. 0.010 M NaI

Calculate the solubility of solid Ca3(PO4)2 (Ksp 5 1.3 3 10232) in a 0.20-M Na3PO4 solution.

Calculate the solubility of solid Pb3(PO4)2 (Ksp 5 1 3 10254) in a 0.10-M Pb(NO3)2 solution.

The solubility of Ce(IO3)3 in a 0.20-M KIO3 solution is 4.4 3 1028 mol/L. Calculate Ksp for Ce(IO3)3

The solubility of Pb(IO3)2(s) in a 0.10-M KIO3 solution is 2.6 3 10211 mol/L. Calculate Ksp for Pb(IO3)2(s).

Which of the substances in Exercises 27 and 28 show increased solubility as the pH of the solution becomes more acidic? Write equations for the reactions that occur to increase the solubility

For which salt in each of the following groups will the solubility depend on pH? a. AgF, AgCl, AgBr c. Sr(NO3)2, Sr(NO2)2 b. Pb(OH)2, PbCl2 d. Ni(NO3)2, Ni(CN)2

What mass of ZnS (Ksp 5 2.5 3 10222) will dissolve in 300.0 mL of 0.050 M Zn(NO3)2? Ignore the basic properties of S22

The concentration of Mg21 in seawater is 0.052 M. At what pH will 99% of the Mg21 be precipitated as the hydroxide salt? [Ksp for Mg(OH)2 5 8.9 3 10212.]

Will a precipitate form when 100.0 mL of 4.0 3 1024 M Mg(NO3)2 is added to 100.0 mL of 2.0 3 1024 M NaOH?

A solution contains 1.0 3 1025 M Ag1 and 2.0 3 1026 M CN2. Will AgCN(s) precipitate? (Ksp for AgCN(s) is 2.2 3 10212.)

A solution is prepared by mixing 100.0 mL of 1.0 3 1022 M Pb(NO3)2 and 100.0 mL of 1.0 3 1023 M NaF. Will PbF2(s) (Ksp 5 4 3 1028 ) precipitate?

A solution contains 2.0 3 1023 M Ce31 and 1.0 3 1022 M IO3 32. Will Ce(IO3)3(s) precipitate? [Ksp for Ce(IO3)3 is 3.2 3 10210.]

Calculate the final concentrations of K1(aq), C2O4 22(aq), Ba21(aq), and Br2(aq) in a solution prepared by adding 0.100 L of 0.200 M K2C2O4 to 0.150 L of 0.250 M BaBr2. (For BaC2O4, Ksp 5 2.3 3 1028 .)

A solution is prepared by mixing 75.0 mL of 0.020 M BaCl2 and 125 mL of 0.040 M K2SO4. What are the concentrations of barium and sulfate ions in this solution? Assume only SO4 22 ions (no HSO4 2) are present.

A 50.0-mL sample of 0.00200 M AgNO3 is added to 50.0 mL of 0.0100 M NaIO3. What is the equilibrium concentration of Ag1 in solution? (Ksp for AgIO3 is 3.0 3 1028 .)

A solution is prepared by mixing 50.0 mL of 0.10 M Pb(NO3)2 with 50.0 mL of 1.0 M KCl. Calculate the concentrations of Pb21 and Cl2 at equilibrium. [Ksp for PbCl2(s) is 1.6 3 1025 .]

A solution contains 1.0 3 1025 M Na3PO4. What is the minimum concentration of AgNO3 that would cause precipitation of solid Ag3PO4 (Ksp 5 1.8 3 10218)?

The Ksp of Al(OH)3 is 2 3 10232. At what pH will a 0.2-M Al31 solution begin to show precipitation of Al(OH)3?

A solution is 1 3 1024 M in NaF, Na2S, and Na3PO4. What would be the order of precipitation as a source of Pb21 is added gradually to the solution? The relevant Ksp values are Ksp(PbF2) 5 4 3 1028 , Ksp(PbS) 5 7 3 10229, and Ksp[Pb3(PO4)2] 5 1 3 10254.

A solution contains 0.25 M Ni(NO3)2 and 0.25 M Cu(NO3)2. Can the metal ions be separated by slowly adding Na2CO3? Assume that for successful separation 99% of the metal ion must be precipitated before the other metal ion begins to precipitate, and assume no volume change on addition of Na2CO3.

Write equations for the stepwise formation of each of the following complex ions. a. Ni(CN)4 22 b. V(C2O4)3 32

Write equations for the stepwise formation of each of the following complex ions. a. CoF6 32 b. Zn(NH3)4 21

In the presence of CN2, Fe31 forms the complex ion Fe(CN)6 32. The equilibrium concentrations of Fe31 and Fe(CN)6 32 are 8.5 3 10240 M and 1.5 3 1023 M, respectively, in a 0.11-M KCN solution. Calculate the value for the overall formation constant of Fe(CN)6 32. Fe31 1aq2 1 6CN2 1aq2mFe1CN2 6 32 1aq2 Koverall 5 ?

In the presence of NH3, Cu21 forms the complex ion Cu(NH3)4 21. If the equilibrium concentrations of Cu21 and Cu(NH3)4 21 are 1.8 3 10217 M and 1.0 3 1023 M, respectively, in a 1.5-M NH3 solution, calculate the value for the overall formation constant of Cu(NH3)4 21. Cu21 1aq2 1 4NH3 1aq2mCu1NH32 4 21 1aq2 Koverall 5 ?

When aqueous KI is added gradually to mercury(II) nitrate, an orange precipitate forms. Continued addition of KI causes the precipitate to dissolve. Write balanced equations to explain these observations. (Hint: Hg21 reacts with I2 to form HgI4 22.)

As sodium chloride solution is added to a solution of silver nitrate, a white precipitate forms. Ammonia is added to the mixture and the precipitate dissolves. When potassium bromide solution is then added, a pale yellow precipitate appears. When a solution of sodium thiosulfate is added, the yellow precipitate dissolves. Finally, potassium iodide is added to the solution and a yellow precipitate forms. Write equations for all the changes mentioned above. What conclusions can you draw concerning the sizes of the Ksp values for AgCl, AgBr, and AgI?

The overall formation constant for HgI4 22 is 1.0 3 1030. That is, 1.0 3 1030 5 3HgI4 22 4 3Hg21 4 3I 2 4 4 What is the concentration of Hg21 in 500.0 mL of a solution that was originally 0.010 M Hg21 and 0.78 M I2? The reaction is Hg21 1aq2 1 4I2 1aq2mHgI4 22 1aq2

A solution is prepared by adding 0.10 mole of Ni(NH3)6Cl2 to 0.50 L of 3.0 M NH3. Calculate [Ni(NH3)6 21] and [Ni21] in this solution. Koverall for Ni(NH3)6 21 is 5.5 3 108 . That is, 5.5 3 108 5 3Ni1NH32 6 21 4 3Ni21 4 3NH3 4 6 for the overall reaction Ni21 1aq2 1 6NH3 1aq2mNi1NH32 6 21 1aq2

A solution is formed by mixing 50.0 mL of 10.0 M NaX with 50.0 mL of 2.0 3 1023 M CuNO3. Assume that Cu1 forms complex ions with X2 as follows: Cu1 1aq2 1 X2 1aq2mCuX1aq2 K1 5 1.0 3 102 CuX1aq2 1 X2 1aq2mCuX2 2 1aq2 K2 5 1.0 3 104 CuX2 2 1aq2 1 X2 1aq2mCuX3 22 1aq2 K3 5 1.0 3 103 with an overall reaction Cu1 1aq2 1 3X2 1aq2mCuX3 22 1aq2 K 5 1.0 3 109 Calculate the following concentrations at equilibrium. a. CuX3 22 b. CuX2 2 c. Cu1

A solution is prepared by mixing 100.0 mL of 1.0 3 1024 M Be(NO3)2 and 100.0 mL of 8.0 M NaF. Be21 1aq2 1 F2 1aq2mBeF1 1aq2 K1 5 7.9 3 104 BeF1 1aq2 1 F2 1aq2mBeF2 1aq2 K2 5 5.8 3 103 BeF2 1aq2 1 F2 1aq2mBeF3 2 1aq2 K3 5 6.1 3 102 BeF3 2 1aq2 1 F2 1aq2mBeF4 22 1aq2 K4 5 2.7 3 101 Calculate the equilibrium concentrations of F2, Be21, BeF1, BeF2, BeF3 2, and BeF4 22 in this solution.

a. Calculate the molar solubility of AgI in pure water. Ksp for AgI is 1.5 3 10216. b. Calculate the molar solubility of AgI in 3.0 M NH3. The overall formation constant for Ag(NH3)2 1 is 1.7 3 107 . c. Compare the calculated solubilities from parts a and b. Explain any differences.

Solutions of sodium thiosulfate are used to dissolve unexposed AgBr (Ksp 5 5.0 3 10213) in the developing process for blackand-white film. What mass of AgBr can dissolve in 1.00 L of 0.500 M Na2S2O3? Ag1 reacts with S2O3 22 to form a complex ion: Ag1 1aq2 1 2S2O3 22 1aq2mAg1S2O32 2 32 1aq2 K 5 2.9 3 1013

Kf for the complex ion Ag(NH3)2 1 is 1.7 3 107 . Ksp for AgCl is 1.6 3 10210. Calculate the molar solubility of AgCl in 1.0 M NH3.

The copper(I) ion forms a chloride salt that has Ksp 5 1.2 3 1026 . Copper(I) also forms a complex ion with Cl2: Cu1 1aq2 1 2Cl2 1aq2mCuCl2 2 1aq2 K 5 8.7 3 104 a. Calculate the solubility of copper(I) chloride in pure water. (Ignore CuCl2 2 formation for part a.) b. Calculate the solubility of copper(I) chloride in 0.10 M NaCl.

A series of chemicals were added to some AgNO3(aq). NaCl(aq) was added first to the silver nitrate solution with the end result shown below in test tube 1, NH3(aq) was then added with the end result shown in test tube 2, and HNO3(aq) was added last with the end result shown in test tube 3.Explain the results shown in each test tube. Include a balanced equation for the reaction(s) taking place.

The solubility of copper(II) hydroxide in water can be increased by adding either the base NH3 or the acid HNO3. Explain. Would added NH3 or HNO3 have the same effect on the solubility of silver acetate or silver chloride? Explain.

A solution contains 0.018 mole each of I2, Br2, and Cl2. When the solution is mixed with 200. mL of 0.24 M AgNO3, what mass of AgCl(s) precipitates out, and what is [Ag1]? Assume no volume change. AgI: Ksp 5 1.5 3 10216 AgBr: Ksp 5 5.0 3 10213 AgCl: Ksp 5 1.6 3 10210

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? Explain.

Tooth enamel is composed of the mineral hydroxyapatite. The Ksp of hydroxyapatite, Ca5(PO4)3OH, is 6.8 3 10237. Calculate the solubility of hydroxyapatite in pure water in moles per liter. How is the solubility of hydroxyapatite affected by adding acid? When hydroxyapatite is treated with fluoride, the mineral fluorapatite, Ca5(PO4)3F, forms. The Ksp of this substance is 1 3 10260. Calculate the solubility of fluorapatite in water. How do these calculations provide a rationale for the fluoridation of drinking water?

The U.S. Public Health Service recommends the fluoridation of water as a means for preventing tooth decay. The recommended concentration is 1 mg F2 per liter. The presence of calcium ions in hard water can precipitate the added fluoride. What is the maximum molarity of calcium ions in hard water if the fluoride concentration is at the USPHS recommended level? (Ksp for CaF2 5 4.0 3 10211)

What mass of Ca(NO3)2 must be added to 1.0 L of a 1.0-M HF solution to begin precipitation of CaF2(s)? For CaF2, Ksp 5 4.0 3 10211 and Ka for HF 5 7.2 3 1024 . Assume no volume change on addition of Ca(NO3)2(s).

Calculate the mass of manganese hydroxide present in 1300 mL of a saturated manganese hydroxide solution. For Mn(OH)2, Ksp 5 2.0 3 10213.

On a hot day, a 200.0-mL sample of a saturated solution of PbI2 was allowed to evaporate until dry. If 240 mg of solid PbI2 was collected after evaporation was complete, calculate the Ksp value for PbI2 on this hot day.

The active ingredient of Pepto-Bismol is the compound bismuth subsalicylate, which undergoes the following dissociation when added to water: C7H5BiO4 1s2 1 H2O1l2mC7H4O3 22 1aq2 1 Bi31 1aq2 1 OH2 1aq2 K 5 ? If the maximum amount of bismuth subsalicylate that reacts by this reaction is 3.2 3 10219 mol/L, calculate the equilibrium constant for the preceding reaction.

Nanotechnology has become an important field, with applications ranging from high-density data storage to the design of nano machines. One common building block of nanostructured architectures is manganese oxide nanoparticles. The particles can be formed from manganese oxalate nanorods, the formation of which can be described as follows: Mn21 1aq2 1 C2O4 22 1aq2mMnC2O4 1aq2 K1 5 7.9 3 103 MnC2O4 1aq2 1 C2O4 22 1aq2mMn1C2O42 2 22 1aq2 K2 5 7.9 3 101 Calculate the value for the overall formation constant for Mn(C2O4)2 22: K 5 3Mn1C2O42 2 22 4 3Mn21 4 3C2O4 22 4 2

The equilibrium constant for the following reaction is 1.0 3 1023: Cr31 1aq2 1 H2EDTA22 1aq2mCrEDTA2 1aq2 1 2H1 1aq2 EDTA42 5 Ethylenediaminetetraacetate N CH2 CH2 N O2C CH2 CH2 O2C CO2 CO2 CH 2 CH2 EDTA is used as a complexing agent in chemical analysis. Solutions of EDTA, usually containing the disodium salt Na2H2EDTA, are used to treat heavy metal poisoning. Calculate [Cr31] at equilibrium in a solution originally 0.0010 M in Cr31 and 0.050 M in H2EDTA22 and buffered at pH 5 6.00.

Calculate the concentration of Pb21 in each of the following. a. a saturated solution of Pb(OH)2, Ksp 5 1.2 3 10215 b. a saturated solution of Pb(OH)2 buffered at pH 5 13.00 c. Ethylenediaminetetraacetate (EDTA42) is used as a complexing agent in chemical analysis and has the following structure: Ethylenediaminetetraacetate N CH2 CH2 N O2C CH2 CH2 O2C CO2 CO2 CH 2 CH2 Solutions of EDTA42 are used to treat heavy metal poisoning by removing the heavy metal in the form of a soluble complex ion. The reaction of EDTA42 with Pb21 is Pb21 1aq2 1 EDTA42 1aq2mPbEDTA22 1aq2 K 5 1.1 3 1018 Consider a solution with 0.010 mole of Pb(NO3)2 added to 1.0 L of an aqueous solution buffered at pH 5 13.00 and containing 0.050 M Na4EDTA. Does Pb(OH)2 precipitate from this solution?

Will a precipitate of Cd(OH)2 form if 1.0 mL of 1.0 M Cd(NO3)2 is added to 1.0 L of 5.0 M NH3? Cd21 1aq2 1 4NH3 1aq2mCd1NH32 4 21 1aq2 K 5 1.0 3 107 Cd1OH2 2 1s2mCd21 1aq2 1 2OH2 1aq2 Ksp 5 5.9 3 10215

a. Using the Ksp value for Cu(OH)2 (1.6 3 10219) and the overall formation constant for Cu(NH3)4 21 (1.0 3 1013), calculate the value for the equilibrium constant for the following reaction: Cu1OH2 2 1s2 1 4NH3 1aq2mCu1NH32 4 21 1aq2 1 2OH2 1aq2 b. Use the value of the equilibrium constant you calculated in part a to calculate the solubility (in mol/L) of Cu(OH)2 in 5.0 M NH3. In 5.0 M NH3 the concentration of OH2 is 0.0095 M

Describe how you could separate the ions in each of the following groups by selective precipitation. a. Ag1, Mg21, Cu21 c. Pb21, Bi31 b. Pb21, Ca21, Fe21

The solubility rules outlined in Chapter 4 say that Ba(OH)2, Sr(OH)2, and Ca(OH)2 are marginally soluble hydroxides. Calculate the pH of a saturated solution of each of these marginally soluble hydroxides

In the chapter discussion of precipitate formation, we ran the precipitation reaction to completion and then let some of the precipitate redissolve to get back to equilibrium. To see why, redo Example 16.6, where Initial Concentration (mol/L) Equilibrium Concentration (mol/L) [Mg21]0 5 3.75 3 1023 [Mg21] 5 3.75 3 1023 2 y [F2]0 5 6.25 3 1022 88888888n [F2] 5 6.25 3 1022 2 2y

Assuming that the solubility of Ca3(PO4)2(s) is 1.6 3 1027 mol/L at 258C, calculate the Ksp for this salt. Ignore any potential reactions of the ions with water.

Order the following solids (ad) from least soluble to most soluble. Ignore any potential reactions of the ions with water. a. AgCl Ksp 5 1.6 3 10210 b. Ag2S Ksp 5 1.6 3 10249 c. CaF2 Ksp 5 4.0 3 10211 d. CuS Ksp 5 8.5 3 10245

The Ksp for PbI2(s) is 1.4 3 1028 . Calculate the solubility of PbI2(s) in 0.048 M NaI.

The solubility of Pb(IO3)2(s) in a 7.2 3 1022 -M KIO3 solution is 6.0 3 1029 mol/L. Calculate the Ksp value for Pb(IO3)2(s).

A 50.0-mL sample of 0.0413 M AgNO3(aq) is added to 50.0 mL of 0.100 M NaIO3(aq). Calculate the [Ag1] at equilibrium in the resulting solution. [Ksp for AgIO3(s) 5 3.17 3 1028 .]

The Hg21 ion forms complex ions with I2 as follows: Hg21 1aq2 1 I 2 1aq2mHgI1 1aq2 K1 5 1.0 3 108 HgI1 1aq2 1 I 2 1aq2mHgI2 1aq2 K2 5 1.0 3 105 HgI2 1aq2 1 I 2 1aq2mHgI3 2 1aq2 K3 5 1.0 3 109 HgI3 2 1aq2 1 I 2 1aq2mHgI4 22 1aq2 K4 5 1.0 3 108 A solution is prepared by dissolving 0.088 mole of Hg(NO3)2 and 5.00 mole of NaI in enough water to make 1.0 L of solution. a. Calculate the equilibrium concentration of [HgI4 22]. b. Calculate the equilibrium concentration of [I2]. c. Calculate the equilibrium concentration of [Hg21].

The copper(I) ion forms a complex ion with CN2 according to the following equation: Cu1 1aq2 1 3CN2 1aq2mCu1CN2 3 22 1aq2 K 5 1.0 3 1011 a. Calculate the solubility of CuBr(s) (Ksp 5 1.0 3 1025 ) in 1.0 L of 1.0 M NaCN. b. Calculate the concentration of Br2 at equilibrium. c. Calculate the concentration of CN2 at equilibrium

Consider a solution made by mixing 500.0 mL of 4.0 M NH3 and 500.0 mL of 0.40 M AgNO3. Ag1 reacts with NH3 to form AgNH3 1 and Ag(NH3)2 1: Ag1 1aq2 1 NH3 1aq2mAgNH3 1 1aq2 K1 5 2.1 3 103 AgNH3 1 1aq2 1 NH3 1aq2mAg1NH32 2 1 1aq2 K2 5 8.2 3 103 Determine the concentration of all species in solution.

a. Calculate the molar solubility of AgBr in pure water. Ksp for AgBr is 5.0 3 10213. b. Calculate the molar solubility of AgBr in 3.0 M NH3. The overall formation constant for Ag(NH3)2 1 is 1.7 3 107 , that is, Ag1 1aq2 1 2NH3 1aq2 h Ag1NH32 2 1 1aq2 K 5 1.7 3 107 . c. Compare the calculated solubilities from parts a and b. Explain any differences. d. What mass of AgBr will dissolve in 250.0 mL of 3.0 M NH3? e. What effect does adding HNO3 have on the solubilities calculated in parts a and b?

Calculate the equilibrium concentrations of NH3, Cu21, Cu(NH3)21, Cu(NH3)2 21, Cu(NH3)3 21, and Cu(NH3)4 21 in a solution prepared by mixing 500.0 mL of 3.00 M NH3 with 500.0 mL of 2.00 3 1023 M Cu(NO3)2. The stepwise equilibria are Cu21 1aq2 1 NH3 1aq2mCuNH3 21 1aq2 K1 5 1.86 3 104 CuNH3 21 1aq2 1 NH3 1aq2mCu1NH32 2 21 1aq2 K2 5 3.88 3 103 Cu1NH32 2 21 1aq2 1 NH3 1aq2mCu1NH32 3 21 1aq2 K3 5 1.00 3 103 Cu1NH32 3 21 1aq2 1 NH3 1aq2mCu1NH32 4 21 1aq2 K4 5 1.55 3 102

Calculate the solubility of AgCN(s) (Ksp 5 2.2 3 10212) in a solution containing 1.0 M H1. (Ka for HCN is 6.2 3 10210.)

Calcium oxalate (CaC2O4) is relatively insoluble in water (Ksp 5 2 3 1029 ). However, calcium oxalate is more soluble in acidic solution. How much more soluble is calcium oxalate in 0.10 M H1 than in pure water? In pure water, ignore the basic properties of C2O4 22.

What is the maximum possible concentration of Ni21 ion in water at 258C that is saturated with 0.10 M H2S and maintained at pH 3.0 with HCl?

A mixture contains 1.0 3 1023 M Cu21 and 1.0 3 1023 M Mn21 and is saturated with 0.10 M H2S. Determine a pH where CuS precipitates but MnS does not precipitate. Ksp for CuS 5 8.5 3 10245 and Ksp for MnS 5 2.3 3 10213

Sodium tripolyphosphate (Na5P3O10) is used in many synthetic detergents. Its major effect is to soften the water by complexing Mg21 and Ca21 ions. It also increases the efficiency of surfactants, or wetting agents that lower a liquids surface tension. The K value for the formation of MgP3O1032 is 4.0 3 108 . The reaction is Mg21 1aq2 1 P3O1052 1aq2 mMgP3O1032 1aq2 . Calculate the concentration of Mg21 in a solution that was originally 50. ppm Mg21 (50. mg/L of solution) after 40. g Na5P3O10 is added to 1.0 L of the solution

You add an excess of solid MX in 250 g water. You measure the freezing point and find it to be 20.0288C. What is the Ksp of the solid? Assume the density of the solution is 1.0 g/cm3

a. Calculate the molar solubility of SrF2 in water, ignoring the basic properties of F2. (For SrF2, Ksp 5 7.9 3 10210.) b. Would the measured molar solubility of SrF2 be greater than or less than the value calculated in part a? Explain. c. Calculate the molar solubility of SrF2 in a solution buffered at pH 5 2.00. (Ka for HF is 7.2 3 1024 .)

A solution saturated with a salt of the type M3X2 has an osmotic pressure of 2.64 3 1022 atm at 258C. Calculate the Ksp value for the salt, assuming ideal behavior.

Consider 1.0 L of an aqueous solution that contains 0.10 M sulfuric acid to which 0.30 mole of barium nitrate is added. Assuming no change in volume of the solution, determine the pH, the concentration of barium ions in the final solution, and the mass of solid formed.

The Ksp for Q, a slightly soluble ionic compound composed of M2 21 and X2 ions, is 4.5 3 10229. The electron configuration of M1 is [Xe]6s1 4f 145d10. The X2 anion has 54 electrons. What is the molar solubility of Q in a solution of NaX prepared by dissolving 1.98 g NaX in 150. mL solution?

Aluminum ions react with the hydroxide ion to form the precipitate Al(OH)3(s), but can also react to form the soluble complex ion Al(OH)4 2. In terms of solubility, Al(OH)3(s) will be more soluble in very acidic solutions as well as more soluble in very basic solutions. a. Write equations for the reactions that occur to increase the solubility of Al(OH)3(s) in very acidic solutions and in very basic solutions. b. Lets study the pH dependence of the solubility of Al(OH)3(s) in more detail. Show that the solubility of Al(OH)3, as a function of [H1], obeys the equation S 5 3H1 4 3 Ksp/Kw 3 1 KKw/3H1 4 where S 5 solubility 5 [Al31] 1 [Al(OH)4 2] and K is the equilibrium constant for Al1OH2 3 1s2 1 OH2 1aq2mAl1OH2 4 2 1aq2 c. The value of K is 40.0 and Ksp for Al(OH)3 is 2 3 10232. Plot the solubility of Al(OH)3 in the pH range 412.