In: Chemistry
Use a mathematical solution to determine the pH of a solution containing 10-2 M propionic acid (C₂H₅COOH; pKa = 4.88).
pKa = 4.88
Ka = 10^-4.88 = 1.32 x 10^-5
C2H5COOH ---------------> C2H5COO- + H+
10^-2 0 0
10^-2 - x x x
Ka = [C2H5COO- ][H+] / [C2H5COOH]
1.32 x 10^-5 = x^2 / 10^-2 - x
x = 3.57 x 10^-4
[H+] = 3.57 x 10^-4 M
pH = -log (3.57 x 10^-4)
pH = 3.45