Question

A buffer solution contains 0.70 mol of hydrocyanic acid (HCN) and 0.76 mol of sodium cyanide (NaCN) in 1.90 L.
The K_a of hydrocyanic acid (HCN) is K_a = 4.9e-10.



(a) What is the pH of this buffer?

pH = ___


(b) What is the pH of the buffer after the addition of 0.28 mol of NaOH? (assume no volume change)

pH = ____


(c) What is the pH of the original buffer after the addition of 0.56 mol of HI? (assume no volume change)

pH = ___