1. Complete the table:
[H3O+] (M)
pH
pOH
[OH-] (M)
Acidic or
Basic?
3.2 x 10-8
4.20
5.50
7.8 x 10-2
2. Consider the reaction: CH3NH2(aq) + H2O(l)  CH3NH3+(aq) + OH-(aq) where Kb = 4.4 X 10-4.
If a 0.25M solution of CH3NH2(aq) is made, what will the pH of this solution be?
3. What is the concentration of hydroxide ions, and what is the pH of an 8.7x10-5M solution
of potassium hydroxide?
4. Write equations for each of the following weak bases to show how they ionize water to
form OH-. Write the base ionization constant expression for these bases.
a) NH3
b) HCO3c) CH3NH2
5. Determine the concentration of OH-, as well as pH and pOH of a 0.15M solution of
ammonia. Kb=1.8x10-5
6. A 0.150M solution of hydrogen carbonite ions (HClO3-) have a pH of 8.5. What is Kb
for hydrogen carbonite ions?
7. An ammonia solution has a pH of 6.5. Kb of ammonia is 1.8x10-5.
a) What is the pOH of this solution?
b) What was the initial concentration of ammonia?
8. Sulfate ions act as a weak base. If a 0.5 M solution of sulfate ions has a pH of 8.2 what
is the value of the base ionization constant?
9. If the initial concentration of barium hydroxide is 0.50M and the pH of the solution is
8.8:
a.
b.
c.
d.
What is the pOH of this solution?
What is the equilibrium concentration of hydroxide ions in this solution?
What is the equilibrium concentration of barium hydroxide?
What is the value of the base ionization constant?
10. Carbonate ions act as a weak base. The base ionization constant for carbonate ions is
3.6x10-5. A solution of carbonate ions produces a pH of 9.6.
a. What is the pOH of this solution?
b. What is the equilibrium concentration of hydroxide ions in this solution?
c. What is the equilibrium concentration of carbonate ions?
d. What was the initial concentration of carbonate ions?