Part 1: In a solution, when the concentrations of a weak acid and its conjugate base are equal, ________.
a. the buffering capacity is significantly decreased
b. the -log of the [H+] and the -log of the Ka are equal
c. All of these are true.
d. the system is not at equilibrium

Part 2:
Of the following solutions, which has the greatest buffering capacity?
a. 0.234 M NH3 and 0.100 M NH4Cl
b. 0.543 M NH3 and 0.555 M NH4Cl
c. 0.100 M NH3 and 0.455 M NH4Cl
d. They are all buffer solutions and would all have the same capacity.
e. 0.087 M NH3 and 0.088 M NH4Cl

Part 3:
Which of the following could be added to a solution of acetic acid to prepare a buffer?
a. sodium hydroxide only
b. hydrofluoric acid or nitric acid
c. sodium acetate only
d. sodium acetate or sodium hydroxide
e. nitric acid only