Quiz
1. A solution of H3PO4 and its associated forms has a pH of 7.50. What
is the principal species? For H3PO4, pKa1 = 2.148, pKa2 = 7.199, pKa3
= 12.15. Show how you came to your answer using equilibrium
reactions.
a. H3PO4
c. HPO42-
b. H2PO4d. PO43-
2. In problem 1 above, what is the second most abundant species?
a. H3PO4
c. HPO42-
b. H2PO4d. PO43-
Quiz
3. How many mL of 0.250 M HCl need to be added to 20.0 mL of
0.350 M acetate to reach the equivalence point? Show your work.
a. 14.0 mL
c. 28.0 mL
b. 20.0 mL
d. none of the above
4. Consider the titration of a weak acid whose pKa is 7.7. What is the
pH of the titration half way to the equivalence point?
a. 7.7
c. 7.0
b. 6.3
d. more information is necessary