the pH of the solution after 10.0, 20.0, and 30.0 mL

A 25.0 mL sample of a 0.080 M solution of aqueous trimethylamine is titrated with a 0.10 M solution of HCl. Calculate the pH of the solution after 10.0, 20.0, and 30.0 mL of acid have been added; pKb of (CH3)3N=4.19 at 25 degrees celsius.