Hydrocyanic acid has a Ka of 4.0 X 10-10. What is the percent of ionization of a 1.0 molar solution?

Question

my answer is 0.004% is this correct?

a) 0.004%
b) 0.0020%
c) 0.0004%
d) 0.02%

Answer 1

How did you get 0.004%? That isn't my answer.

Answer 2

Hydrocyanic acid has a Ka of 4.0 X 10-10. What is the percent of ionization of a 1.0 molar solution?
my answer is 0.004% is this correct?
(4.0 x 10-10)/1.0 x 100 this wrong?

a) 0.004%
b) 0.0020%
c) 0.0004%
d) 0.02%