Chemistry
posted by Sharon on .
For a solution that is 0.20 M HCN(aq) with a Ka=4.9x10^10
a. calculate the [H+]
b. calculate the [OH]
c. what's the pH?
Please show your work on how to solve it. Thank you

.............HCN ==> H^+ + CN^
initial....0.20M.....0.....0
change......x.......+x.....+x
final.... 0.20x......x.....x
Ka = ((H^+)(CN^)/(HCN)
Substitute from the above and solve for (H^+).
pH = log(H^+)
pH + pOH = pKw = 14
Post your work if you get stuck. 
Thanks! That was helpful.