Question

12.) An acid has a Ka = 1.0 x 10-6. At what pH would this acid and its corresponding salt make a good buffer?

a.) 4
b.) 5
c.) 6
d.) 7
e.) not enough info is given to determine this answer.

13.) A weak acid, HA has a Ka= 1.00 x 10-3. If [HA] = 1.00 M, what must [A-] be for the pH to be 2.70?

a.) 0.50 M b.) 2.0 M c.) 2.7 M d.) 0.37 M

14.) Which of the following is not true of a titration curve for the titration of a weak base with a strong acid?

a.) the beginning pH value is >7.0.
b.) the pH change is gradual until you are near the equivalence point.
c.) the equivalence point would have pH < 7.0
d.) beyond the equivalence point, pH decreases very slowly.
e.) more than one of the statements above is not true of a WB/SA titration.

15.) The molar solubility of CaF2 (s) is 2.1 x 10-4 M. What is the Ksp value for this salt?

16.) Which of the following salts has the lowest solubility in water?

17.) An aqueous solution of barium nitrate is added dropwise to a solution containing 0.10 M sulfate ions and 0.10 M fluoride ions. The Ksp value for barium sulfate = 1.1 x 10-10 and the Ksp value for barium fluoride = 1.7 x 10-6
a.) Which salt will precipitate from solution first?

b.) What is the minimum [Ba2+] concentration necessary to precipitate the first salt? c.) What is the minimum [Ba2+] concentration necessary to precipitate the second salt?

Answer 1