Think you’ve got your head wrapped around Acids and Bases? Put your knowledge to
the test. Good luck — the Stickman is counting on you!
Q. What is the pH of 0.2 M carbonic acid solution (Ka1 = 4.3 × 10-7 and Ka2 = 5.6 × 10-11)?
10.25
3.75
3.53
2.35
6.37
Q. Which of the following is the strongest acid?
H3PO4
H2PO4-
HPO42-
PO43-
SO42-
Q. Thymolphthalein is a pH indicator with a Ka of 1.26 × 10-10. What solution pH could this indictor, which is colorless when protonated and blue when deprotonated, be readily used to determine?
2.5
4.1
12.7
9.8
7.8
Q. Approximately what percentage of a buffer is in its conjugate base form when the buffer pH is 4 units below the pKa of the weak acid buffer?
4%
1%
0.01%
Not enough information provided
99.99%
Q. Approximately what percent dissociated is a 0.35 M buffer solution of HF at pH 4.46?
99%
91%
9%
1%
96.5%
Q. In a weak acid or base solution, the _____________ reaction ______________.
principle; does not significantly contribute to the final equilibrium concentration of H+
principle; may or may not contribute to the final equilibrium concentration of H+ depending on the concentration of reactants
subsidiary; significantly contributes to the final equilibrium concentration of H+
subsidiary; does not significantly contribute to the final equilibrium concentration of H+ and does not need to be considered to accurately compute the pH
subsidiary; does not significantly contribute to the final equilibrium concentration of H+ but may need to be considered to accurately compute the pH if the reactant concentrations are high enough
Q. Suppose 50 mLs of a 0.65 M HCl solution is added to a 1.7 g antacid tablet consisting of a weak base and a nonreactive compound. 15 mLs of 0.34 M NaOH is needed to bring the HCl/antacid solution to pH 7. How many moles of HCl can 1 g of antacid neutralize?
0.027
0.0051
0.016
0.019
0.022
Q. What ratio of NH3 to NH4Cl would be needed to prepare a solution of pH 9.00 (the Ka for NH4+ is 5.8 × 10-10)?
0.38
1.74
1
0.58
2.63
Q. The pKa of imidazole is 7.05. At what pH is imidazole 6% dissociated?
0.42
5.83
8.24
5.86
7.00
Q. A polyprotic acid is ________.
an acid that has more than one H atom
an acid that has more than one dissociable H atom
always more acidic than a monoprotic acid
unstable
not appropriate to use to buffer a solution