SCH4U/R Worksheet
Solubility Equilibrium and Acid-Base Systems Review
1. Silver carbonate, Ag2CO3(s), exhibits low solubility in distilled water at SATP conditions.
a. Write the solubility equilibrium that occurs in a saturated Ag2CO3(aq) solution.
b. Look up the solubility product constant, Ksp, in Appendix C8 and determine the molar solubility of silver
carbonate, Ag2CO3.
c. Complete the concentration-time graph (Fig. 1) up to the first dashed line representing the dissolution
of silver carbonate in deionized water to create a saturated solution.
Figure 1. Solubility equilibrium of silver carbonate
Conc.
(mol/L)
Reaction Progress
(1) cold bath
(2) conc. HCl(aq)
d. To start interval (1), the system is placed into a cold bath. Demonstrate the effect this will have on
concentrations by continuing the graph. What happens to the value of Ksp at this new temperature?
e. Once equilibrium has been reached again, drops of concentrated HCl(aq) are added to the solution at the
start of interval (2). Demonstrate the effect this will have on concentrations. Justify your prediction.
2. A saturated solution of silver sulfate, Ag2SO4(aq), is prepared by adding about 5 g of silver sulfate to 200 mL of
distilled water. The next day, any undissolved silver sulfate had settled to the bottom of the container. This
mixture was filtered to remove the excess solid from the solution.
After the filtration, a 50.00-mL sample of the saturated solution was transferred to an evaporating dish. The dish
is heated to remove all of the water, leaving behind a white crust of silver sulfate. The mass of the remaining
silver sulfate is found to be 0.25 g.
a. Using this empirical evidence, calculate the molar solubility of silver sulfate under these conditions.
b. From the molar solubility that was determined, determine the Ksp of silver sulfate.
3. Phenol, C6H5OH(s), was used during World War II in the Nazi euthanasia program, Aktion T4, for a lethal injection
to the heart where as little as 1 g of the chemical in solution caused instant death to the recipient of the dose.
a. In aqueous form, phenol is often referred to as carbolic acid, C6H5OH(aq). Using a chemical equation,
demonstrate how it produces an acidic solution.
b. A 0.025 M C6H5OH(aq) solution has a pH of 5.80. Determine the percent ionization of phenol.
c. Trimethylamine, (CH3)3N(l), is an organic base. When dissolved in aqueous solution, it produces
hydroxide ions. Using a chemical equation, demonstrate the basicity of trimethylamine.
d. A 0.010 M (CH3)3N(aq) solution has a pH of 10.90. Determine the value of the base ionization constant, Kb,
for trimethylamine.
4. Aqueous solutions containing the aluminum ion, Al3+(aq), exhibit acidic properties (Eq. 1).
Al(H2O)63+(aq)
Equation 1
+
H2O(l)

Al(H2O)5(OH)2+(aq)
+
H3O+(aq)
a. Using the acid ionization constant (Ka) provided in Appendix C8, determine the percent ionization of a
0.50 mol/L aqueous aluminum nitrate solution, Al(NO3)3(aq).
b. Aqueous zinc nitrate, Zn(NO3)2(aq), similarly produces an acidic solution when tested for pH. If an
aqueous solution of 0.50 mol/L Zn(NO3)2(aq) has a pH of 4.35, explain which metal ion is more acidic:
aqueous zinc, Zn2+(aq), or aqueous aluminum, Al3+(aq).
c. Explain the differences in acidity strength of the two metal ions.
5. Chlorine-containing compounds such as sodium hypochlorite, NaClO(s), are added to backyard swimming pools
to kill the microorganisms in pool water and oxidize organic matter in the pool. Once dissolved in water, the
hypochlorite ion, ClO-(aq), forms the equilibrium shown by Eq. 2.
Equation 2
ClO-(aq) +
H2O(l)

OH-(aq) +
HClO(aq)
a. Calculate the base ionization constant, Kb, for the hypochlorite ion if the pH of a 0.100 mol/L NaClO(aq)
solution is 10.25.
b. Superchlorination or “shock treatment” is sometimes necessary with outdoor swimming pools. This
involves adding acidic chemicals, such as pH Minus ®, a pool treatment agent composed of 100 %
sodium hydrogen sulfate, NaHSO4(s).
Explain how a salt compound, such as sodium hydrogen sulfate, causes acidity using chemical
reactions/equilibria to support your explanation.
The pH of the backyard pool must be maintained —the pH of human tears is ideal.
To accomplish this, the concentration of hypochlorous acid and the hypochlorite
ion are approximately equal in the equilibrium shown by Eq. 3.
Equation 3
HClO(aq) +
H2O(l)

H3O+(aq) +
ClO-(aq)
c. Calculate pool pH when hypochlorous acid, HClO(aq), and hypochlorite,
ClO-(aq), have equal concentrations.
d. Considering LeChatelier’s Principle, how will this mixture react upon
addition of strong base to maintain a constant pH of the pool water?