A buffer solution was prepared by adding 495 g of sodium

Question

A buffer solution was prepared by adding 4.95 g of sodium acetate (NaCH3CO2) to 0.250 L of 0.150 M acetic acid (Ka = 1.75 x 10-5).

a. What is the pH of the buffer?

b. What is the pH of the resulting solution if you add 80.0 mg of NaOH to 0.100 L of the buffer?