When all the following solutes act as acids, the one with the weakest conjugate base is

a. H2SO3.

b. H2CO3.

c. HClO4.

d. HClO.

e. HF.

4. (Points: 1)
A sample of ammonia (Kb = 1.8 * 10^-5) is titrated with 0.1 M H2SO4. At the equivalence point, the pH is approximately

a. 1.

b. 5.

c. 7.

d. 9.

e. 11.