If you make a solution in the laboratory that contains 0.1 M acetic acid (CH3COOH), what concentration of hydronium will you have once the solution equilibrates?

acetic acid = HAc

......HAc + H2O ==> H3O^+ + Ac^-
I....0.1......0......0
C....-x.......x......x
E...0.1-x.....x......x

Substitute the E line into the Ka expression and solve for H3O^+