Special Types of Equilibrium Review - DVORSKY
January 13th 2012
1. Define the common-ion effect in your own words.
2. Compare and contrast conjugate acids and conjugate bases.
3. Explain why pH is not used to classify acids and bases as strong or weak.
4. Describe how the hydronium ion forms when an acid is added to water.
5. Explain why the common-ion effect is simply an application of Le Chatalier’s principle.
6. What is the molar solubility of lead (II) chloride, PbCl2(s), with Ksp = 1.7 x 10-5 in:
a) pure water
b) a solution of 0.0185 mol/L sodium chloride
c) Explain the diffence between the answers to parts (a) and (b)
7. Write the three acid-dissociation constant expressions for arsenic acid, H3AsO4(aq). Include the
reactions that are used for these constant expressions.
8. A weak base with a molecular mass of 146.21 g/mol is prepared by dissolving 7.25 g of the substance
into 1.00 L of solution. The pH of the resulting solution was found to be 9.12. Calculate the baseionization constant for this weak base.
9. Name and write the formula for the conjugate acid of each molecule or ion below:
a) NO3-(aq)
b) OH-(aq)
c) H2O(l)
d) HCO3-(aq)
10. A 1.55 mol/L hydrochloric acid solution, HCl(aq), is at 25oC. Determine the hydroxide ion, OH-(aq),
concentration of this solution.
11. What is the hydronium ion concentration of a solution at 25oC with a pOH of 7.95?
12. Write equilibrium equations for each of the following reactions. State whether the reactants or the
products are favoured. Use table of acid/base strengths.
a) Aqueous carbonic acid, H2CO3(aq) is combined with ammonia, NH3(g)
b) Hydrofluoric acid, HF(aq) is mixed with potassium nitrate KNO3(s).
13. Nitrobenzene is a monoprotic organic acid that has many uses, one of which is the manufacturing of
shoe and floor polishes. Ka = 1.05 x 10-4. The ionization of the acid is given by the following reaction:
C6H5NO2(aq) + H2O(l) ⇌ C6H4NO2-(aq) + H3O+(aq)
Determine the pH of a 0.10 mol/L solution of the acid.
14. Which solution has a higher concentration of hydronium ion: a 0.0042 mol/L solution of a weak
monoprotic acid with Ka = 1.58 x 10-4 or a 0.035 mol/l solution of a weak monoprotic acid with Ka = 2.27
x 10-4?
15. The Ksp for iron (II) hydroxide, FeOH2(s) is 4.9 x 10-17. What mass (in grams) of the solid can be
dissolved in 100.00 L of solution?
16. Mr. Dvorsky determines that the solubility of silver chromate, Ag2CrO4(s) is 21.7 mg/L. What is the
solubility-product constant for this solid?
17. What is the hydroxide ion concentration in a solution of 0.45 mol/L hydrochloric acid, a strong acid.
18. Shortly before fainting, Mr. Dvorsky determines that his blood at 25oC contains a hydroxide ion
concentration of 2.50 x 10-7 mol/L. What is the hydronium ion concentration of his blood and what is the
pH?
19. What is the pH of a 0.100 mol/L weak base solution with a Kb value of 1.68 x 10-6?
20. What type of solution will form when sodium acetate, NaCH3COO(s) dissolves in water?