5. Calculate the concentration of calcium ions in a saturated calcium phosphate solution.
(
K
sp
for Ca
3
(PO
4
)
2
= 1.3 X 10
-26
)
a.
1.2 x 10
-5
mol/L
b.
2.0 x 10
-5
mol/L
c.
6.6 x 10
-6
mol/L
d.
7.8 x 10
-6
mol/L
e.
8.3 x 10
-6
mol/L
6. Calculate the molar solubility of silver carbonate in 1.0
M
sodium carbonate solution.
(
K
sp
for Ag
2
CO
3
= 8.1 x 10
-12
)
a.
8.1 x 10
-12
M
b.
2.8 x 10
-6
M
c.
1.4 x 10
-6
M
d.
1.4 x 10
-8
M
e.
2.0 x 10
-4
M
7. Calculate the pH of a solution necessary to just begin the precipitation of Mg(OH)
2
when [Mg
2+
] = 0.001
M
. (
K
sp
for Mg(OH)
2
= 1.2 x 10
-11
)
a. 11
b. 10
c. 9
d. 8
e. 4
8. In qualitative analysis, the metals of Ion Group 1 can be separated from other ions by
precipitating them as chloride salts. A solution initially contains Ag
+
and Pb
2+
at a
concentration of 0.10
M
. Aqueous HCl is added to this solution until the Cl
-
concentration
is 0.10
M
. What will the concentrations of Ag
+
and Pb
2+
be at equilibrium?
(
K
sp
for AgCl = 1.8 x 10
-10
;
K
sp
for PbCl
2
= 1.7 x 10
-5
)
a. [Ag
+
] = 1.8 x 10
-11
M
; [Pb
2+
] = 1.7 x 10
-6
M
b. [Ag
+
] = 1.8 x 10
-7
M
; [Pb
2+
] = 1.7 x 10
-4
M
c. [Ag
+
] = 1.8 x 10
-11
M
; [Pb
2+
] = 8.5 x 10
-5
M
d. [Ag
+
] = 1.8 x 10
-9
M
; [Pb
2+
] = 1.7 x 10
-3
M
e. [Ag
+
] = 1.8 x 10
-9
M
; [Pb
2+
] = 8.5 x 10
-6
M
9. Silver chloride is relatively insoluble in water (
K
sp
for AgCl = 1.8 x 10
-10
) but it is
soluble in aqueous ammonia, due to the formation of the complex ion Ag(NH
3
)
2
+
. How
many moles of AgCl will dissolve in 1.00 L of solution containing 6.0 moles of free
NH
3
? (
K
f
for Ag(NH
3
)
2
+
= 1.7 x 10
7
)
a. 9.1 x 10
-6
mol
b. 2.9 x 10
-4
mol
c. 0.0091 mol
d. 0.084 mol
e. 0.33 mol