Hence the acid has no effect on the solubility of hg

Hence, the acid has no effect on the solubility of
Hg
2
I
2
.
MgF
2
←
→
Mg
2+
+ 2F
-
F - + H
3
O +
←
→
HF + H
2
O
Since the concentration of F
-
is decreasing, according to LeChatelier the equilibrium
equation will shift to the right; i.e., the solubility of MgF
2
will increase.
43. CHEM 162-2000 FINAL EXAM
EQUILIBRIA
SOLUBILITY PRODUCT
What is the molar solubility of CaF
2
in a 0.50 M aqueous solution of KF at 25 o C?
K
sp
for CaF
2
= 4.0 x 10
–11
at 25
o
C.
E
8. CHEM 162-2000 HOURLY EXAM III
EQUILIBRIA
SOLUBILITY PRODUCT
Calculate the mass of MgF
2
(s) needed to prepare 500 mL of a saturated aqueous solution at
25 o C.
K
sp
for MgF
2
(s) = 3.7 x 10 -8 at 25 o C
molar mass of MgF
2
= 64.3 g/mol
-
Chapter 15B practice problems 27

14. CHEM 162-2000 HOURLY EXAM III
EQUILIBRIA
SOLUBILITY PRODUCT
Three chemistry professors mixed aqueous solutions of Ba(NO
3
)
2
and (NH
4
)
2
CO
3
as
specified below. Which of the professors was/were successful in producing a precipitate of
barium carbonate? K
sp
= 8 x 10
-9
for BaCO
3
.
Ba(NO
3
)
2
(NH
4
)
2
CO
3
Prof. Cotter: 100 mL of 1 x 10
-2
M 100 mL of 1 x 10
-2
Prof. Erenrich 10 mL of 1 x 10 -3 M 10 mL of 1 x 10 -3
Prof. Kimmel 1 mL of 1 x 10 -3 M 1 mL of 1 x 10 -3 M
M
M
Chapter 15B practice problems 28

Chapter 15B practice problems 29

23. CHEM 162-2000 HOURLY EXAM III
EQUILIBRIA
SOLUBILITY PRODUCT
What is the solubility of Ag
2
SO
4
in 2.0 M Na
2
SO
4
(aq) at 25 o C?
K
sp
for Ag
2
SO
4
= 1.7 x 10
–5
at 25
o
C
A. 2.6 x 10
-2
M
B. 2.1 x10 –6 M
C. 4.1 x 10
–3
M
D. 6.4 x 10 -3 M
E
. 1.5 x 10 –3 M.
25. CHEM 162-2000 HOURLY EXAM III
EQUILIBRIA
SOLUBILITY PRODUCT
Which of the following sparingly soluble salts would be more soluble in an acidic solution
than in pure water?
I. PbI
2
II. PbF
2
III. CaCO
3
IV. Ag
3
PO
4
PbI
2
←
→
Pb
2+
+ 2I
-
I
-
+ H
3
O
+
←
→
No reaction, because I
-
is the conjugate base of a strong acid, and therefore
doesn’t react with H
3
O
+
. Hence, the acid has no effect on the solubility of PbI
2
.
PbF
2
←
→
Pb
2+
+ 2F
-
Chapter 15B practice problems 30