Aqueous Equilibrium - Slightly Soluble SaltsExamples ofMultiple Choice Questions

1.
The solubility product expression for tin(II) hydroxide, Sn(OH)2, is
(a) [Sn2+][OH-]
(b) [Sn2+]2[OH-]
(c) [Sn2+][OH-]2
(d) [Sn2+]3[OH-]
(e) [Sn2+][OH-]3

2.
The solubility product expression for silver(I) sulfide, using x to represent the molar concentration of silver(I) and y to represent the molar concentration of sulfide, is formulated as:
(a) xy
(b) x2y
(c) xy2
(d) x2y2
(e) xy3

3.
Consider the following solubility data for various chromates at 25oC.
 Ksp Ag2CrO4 9.0 x 10-12 BaCrO4 2.0 x 10-10 PbCrO4 1.8 x 10-14
The chromate that is the most soluble in water at 25oC on a molar basis is:

(a) Ag2CrO4
(b) BaCrO4
(c) PbCrO4
(d) impossible to determine
(e) none of these

4.
The molar solubility of PbBr2 is 2.17 x 10-3 M at a certain temperature. Calculate Ksp for PbBr2.
(a) 6.2 x 10-6
(b) 6.4 x 10-7
(c) 4.1 x 10-8
(d) 3.4 x 10-6
(e) 1.4 x 10-5

5.
The solubility of silver sulfate in water at 100oC is approximately 1.4 g per 100 mL. What is the solubility product of this salt at 100oC?
(a) 5.7 x 10-8
(b) 3.5 x 10-7
(c) 8.3 x 10-6
(d) 4.1 x 10-5
(e) 3.6 x 10-4

6.
What is the molar solubility, s, of Ba3(PO4)2 in terms of Ksp?
(a) s = Ksp1/2
(b) s = Ksp1/5
(c) s = [Ksp/27]1/5
(d) s = [Ksp/108]1/5
(e) s = [Ksp/4]5

7.
For Cu(OH)2, Ksp = 1.6 x 10-19. What is the molar solubility of Cu(OH)2?
(a) 3.4 x 10-7 M
(b) 6.4 x 10-7 M
(c) 2.7 x 10-11 M
(d) 5.1 x 10-10 M
(e) 1.7 x 10-10 M

8.
Many lead salts are often used as pigments. If PbSO4 were used in an unglazed ceramic bowl, how many milligrams of lead(II) could dissolve per liter of water?
(a) 43
(b) 35
(c) 11
(d) 28
(e) 53

9.
Ag3PO4 would be least soluble at 25oC in
(a) 0.1 M AgNO3
(b) 0.1 M HNO3
(c) pure water
(d) 0.1 M Na3PO4
(e) solubility in (a), (b), (c), or (d) is not different

10.
The molar solubility of PbCl2 in 0.20 M Pb(NO3)2 solution is:
(a) 1.7 x 10-4 M
(b) 9.2 x 10-3 M
(c) 1.7 x 10-5 M
(d) 4.6 x 10-3 M
(e) 8.5 x 10-5 M

11.
When we mix together, from separate sources, the ions of a slightly soluble ionic salt, the salt will precipitate if Qsp _____ Ksp, and will continue to precipitate until Qsp _____ Ksp.
(a) is greater than; equals
(b) is less than; is greater than
(c) is less than; equals
(d) equals; is less than
(e) equals; is greater than

12.
Which of the following pairs of compounds gives a precipitate when aqueous solutions of them are mixed? Assume that the concentrations of all compounds are 1.0 M immediately after mixing.
(a) CuBr2 and K2CO3
(b) HNO3 and NH4I
(c) BaCl2 and KClO4
(d) Na2CO3 and H2SO4
(e) KCl and KNO3

13.
A swimming pool was sufficiently alkaline so that CO2 absorbed from the air produced in the pool a solution which was 2 x 10-4 M in CO32- M. If the pool water was originally 4 x 10-3 M in Mg2+, 6 x 10-4 M in Ca2+ and 8 x 10-7 M in Fe2+, then a precipitate should form of:
(a) only MgCO3
(b) only CaCO3
(c) only FeCO3
(d) only CaCO3 and FeCO3
(e) MgCO3, CaCO3 and FeCO3

14.
When equal volumes of the solutions indicated are mixed, precipitation should occur only for:
(a) 2 x 10-3 M Mg2+ + 2 x 10-3 M OH-
(b) 2 x 10-1 M Ba2+ + 2 x 10-3 M F-
(c) 2 x 10-3 M Ca2+ + 2 x 10-2 M OH-
(d) 2 x 10-3 M Ca2+ + 2 x 10-3 M OH-
(e) 2 x 10-4 M Pb2+ + 2 x 10-5 M SO42-

15.
At what pH will Cu(OH)2 start to precipitate from a solution with [Cu2+] = 0.0015 M?
(a) 9.0
(b) 8.0
(c) 6.0
(d) 9.4
(e) 4.6

16.
What is the pH of a saturated solution of Mg(OH)2?
(a) 3.5
(b) 10.1
(c) 10.9
(d) 10.5
(e) 9.2

17.
Which solid will precipitate first if an aqueous solution of Na2CrO4 at 25oC is slowly added to an aqueous solution containing 0.001 M Pb(NO3)2 and 0.100 M Ba(NO3)2 at 25oC?
(a) BaCrO4(s)
(b) NaNO3(s)
(c) PbCrO4(s)
(d) Pb(NO3)2(s)
(e) none of these

18.
A solution is 0.0010 M in both Ag+ and Au+. Some solid NaCl is added slowly until the solid AgCl just begins to precipitate. What is the concentration of Au+ ions at this point? Ksp for AgCl = 1.8 x 10-10 and for AuCl = 2.0 x 10-13.
(a) 2.0 x 10-10 M
(b) 4.5 x 10-7 M
(c) 1.8 x 10-7 M
(d) 3.0 x 10-4 M
(e) 1.1 x 10-6 M

1. (c) 2. (b) 3. (a) 4. (c) 5. (e) 6. (d) 7. (a) 8. (d) 9. (a) 10. (d) 11. (a) 12. (a) 13. (d) 14. (a) 15. (c) 16. (d) 17. (c) 18. (e)