Chem
posted by Charlie .
The following questions refer to the following system:
A total of 30.0 mL of a .10M solution of a monophonic acid (Ka = 1.0 x 10 ^5) is titrated with .20M sodium hydroxide solution.
1) Before the titration begins, the pH of the solution is about
A) 2
B) 5
C) 7
D) 9
E) 12
2) Af the equivalence point, the pH of the solution is about
A) 2
B) 5
C) 7
D) 9
E) 12
3) The amount of NaOH required to reach the equivalence point is
A) 15.0 mL
B) 30.0 mL
C) 45.0 mL
D) 50.0 mL
E) 60.0 mL
4) The approximate pH of the solution when the weak acid is half neutralized is
A) 2
B) 5
C) 7
D) 9
E) 12
5) What is true of a buffer made from the weak acid that has a pH of 4.0?
A) [HA] = [A]
B) [HA] = 10[A]
C) 10[HA] = [A]
D) 2[HA] = [A]
E) [HA] = 2[A]
Explanations would be appreciated

I strongly suspect you know how to do some of these and for those it's redundant for me to help. Post your work on what you know and clearly explain what you don't understand about the others and I'll help you through them.