(i) Write the chemical equation for the reaction that occurred in the test tube.
(ii) Which salt has the greater value of
K
sp
: AgBr or AgI ? Justify your answer.
1998 A (Required)
Solve the following problem related to the solubility equilibria of some metal hydroxides in
aqueous solution.
(a)
The solubility of Cu(OH)
2
(s)
is 1.72
10
-6
gram per 100. milliliters of solution at 25
C.
(i)
Write the balanced chemical equation for the dissociation of Cu(OH)
2
(s)
in aqueous
solution.
(ii) Calculate the solubility (in moles per liter) of Cu(OH)
2
at 25
C.
(iii)
Calculate the value of the solubility-product constant,
K
sp
, for Cu(OH)
2
at 25
C.
(b)
The value of the solubility-product constant,
K
sp
,
for Zn(OH)
2
is 7.7
10
-17
at 25
C.
(i)
Calculate the solubility (in moles per liter) of Zn(OH)
2
at 25
C in a solution with a pH of
9.35.
(ii) At 25
C, 50.0 milliliters of 0.100-molar Zn(NO
3
)
2
is mixed with 50.0 milliliters of 0.300-
molar NaOH. Calculate the molar concentration of Zn
2+
(aq)
in the resulting solution once
equilibrium has been established. Assume that volumes are additive.
