CHE 160
ACID BASE REVIEW
SPRING 07
1. What is the pH of a solution obtained when 125 mL of 0.606 M NaOH is diluted to 15.0 L wit whater?
2. If 25.00 mL of HNO3 with a pH of 2.12 is mixed with 25.00 mL of KOH(aq) solution with a pH of
12.65. What is the pH of the final solution?
3. A saturated aqueous solution of o-nitrophenol, HOC6H4NO2, has a pH = 4.53. What is the solubility of
o-nitrophenol in water, in grams per liter? HOC6H4NO2 + HOH ↔ H3O+ -OC6H4NO2 pKa =7.23
4. One handbook lista s value of 9.5 for pKb of quinoline, C9H7N, a weak base used as a preservative for
anatomical specimens and to make dyes. Another handbook lists the solubility of quinoline in water at
25° C as 0.6g/100mL. Use this information to calculate the pH of a saturated solution of quinoline in
water.
5. Calculate [H3O+], [HSO4-], and [SO42-] in 0.75 M H2SO4.
6. Pyridine, C5H5N (pKb = 8.82), forms a salt, pyridinium chloride, as a result of a reaction with HCl.
Write an ionic equation to represent the hydrolysis of the pyridinium ion and calculate the pH of 0.0482
M C5H5NH+Cl7. Calculate [OH-] in a solution that is 0.0062 M Ba(OH)2 and 0.0105 M BaCl2.
8. The H2PO4-/HPO42- buffer is used in maintaining blood pH.
a. Write equations showing how a solution containing these ions reacts with both acid and base.
b. Verify that this buffer is most effective at pH 7.2
c. Calculate the pH of a buffer solution in which [H2PO4-] =0.050 M and [HPO42-]=0.150 M
9. You prepare a buffer solution by dissolving 2.00 g each benzoic acidm, HC7H5O2, and sodium benzoate,
NaC7H5O2, in 750.0 mL of water.
a. What is the pH of this buffer? Assume that the solution’s volume is 750.0 mL.
b. Which buffer component, and how much ( in grams), would you add to 750.0 mL of buffer
solution to change its pH to 4.00?
10. A 25.00 mL sample of H3PO4 (aq) requires 31.15 mL of 0.2420 M KOH for titration to the second
equivalence point. What is the molarity of the H3PO4?
11. Determine the following characteristics of the titration curve for 20.0 mL of 0.275 M NH3(aq) titrated
with 0.325 M HI(aq).
a. the initial pH
b. the volume of 0.325 M HI (aq) at the equivalence point
c. the pH at the half-neutralization point
d. the pH at the equivalence point