ChemBytes - Chapter 8

Answers

CHEMBytes: Additional Problems on Acids/Bases
  1. A saturated solution of lanthanum iodate, La(IO3)3, in pure water has a concentration of iodate ion equal to 2.07 x 10-3 mol L-1 at 25°C. Find [La3+] and the solubility product of lanthanum iodate. Ans: [La3+] = 6.9 x 10-4 M; Ksp = 6.1 x 10-12
  2. Calculate the solubility of lead sulfate in a solution whose pH is 1.0, given the solubility product for PbSO4 to be 1.8 X 10-8. Ans: 3.9 x 10-4 M
  3. An unknown student takes an unknown weight of an unknown acid, dissolves it in an unknown amount of water, and titrates it with a strong base of unknown concentration. When he has added 10.00 mL of base, he notices that the pH is 5.0. He continues the titration until he reaches the equivalence point for removal of on proton. At this point, his buret reads 22.22 mL. What is the dissociation constant of the acid? Ans: Ka = 8.2 x 10-6
  4. What is the pH of a solution prepared by adding 300 mL of 0.500 M H3PO4 to 250 mL of 0.300 M NaOH. Ans: 2.12