The active ingredient in aspirin is acetylsalicylic acid (HC₉H₇O₄), which has a K_aof 3.00 x 10^-4. A 325-mg tablet of aspirin is dissolved in 25.00 mL of water, and the solution is titrated with 0.0500 M NaOH. 

a) Calculate the initial pH of the aspirin solution.

b) What is the pH of the solution after 10.0 mL of NaOH is added?

c) How many mL of NaOH are required to reach the equivalence point? 

d) What is the pH of the solution at the equivalence point?

e) Make a rough sketch of the titration curve for this titration. Label the buffer region and the equivalence point.