Calculate the [CH3CO2H] in a solution if it has a pH 3.21.

Question

CH3CO2H = CH3CO2- + H+

Answer 1

pH = 3.21
3.21 = -log(H^+). Solve for (H^+) equal ESTIMATED 6.2E-4 but you should do it more accurately.
Call CH3COOH =-HAc
........HAc ==> H^+ + Ac^-
I.......x.......0......0
C.....6.2E-4..6.2E-4..6.2E-4
E....x-6.2E-4..6.2E-4.6.2E-

K = (H^+)(Ac^-)/(HAc)
Substitute and solve for x.