In: Chemistry
What is the pH of a buffer made by combining 55.0 ml of 0.450 M
HCN and 45.0 ml of 0.250 M NaCN?
(Ka of HCN = 4.4 x 10^-10) Use the Henderson Hasselbach equation,
and prove why you can use it.
this is a buffer, as stated, use HH equation
pH = pKa + log(NaCH/HCN)
recalculate mmoles in solutino
mmol of NaCN = MV = 45*0.25 = 11.25
mmol of HCN = MV = 0.45*55 = 24.75
pKa 0 -log(HACN) - log(4.4*10^-10) = 9.3565
pH = 9.3565 + log(11.25/24.75)
pH = 9.0140