If C/Ka > 500, the approximate formula can be used to calculate:

c(h+)=[c(HCN)* ka]^ 1/2；

α = C(H+)/0.02

According to the dilution law:

α = [k/c] 1/2 It is known that the relationship between acid concentration and ionization constant and ionization degree of different weak acids with the same concentration is shown in the formula.