A buffer is prepared by adding 300.0 mL of 2.0 M NaOH to 500.0 mL of 2.0 M CH3COOH (Ka = 1.8 × 10–5). What is the pH of this buffer? 0.10 mol of HCl is now added to this buffer (assume no volume change due to the addition of HCl), what is the pH now? Now you add 0.120 mol of NaOH to the original buffer solution (before the addition of HCl) (again assume no change in volume due to the addition of NaOH)