A buffer is prepаred which cоntаins 0.12 M nitrоus аcid, HNO2, and 0.15 M sоdium nitrite, NaNO2. (Ka = 4.5 x 10-4) a) Calculate the pH of the buffer. b) Calculate the pH after 0.015 mol of NaOH is added to 1.00 L of the buffer. c) Calculate the pH after 0.015 mol of NaOH is added to 1.00 L of water.