Question

Acetic acid is 3% dissociated in a 0.02M solution. Give the concentrations of each of the two ions, the acetic acid, and the Ka for acetic acid.

HC2H3O2 ==> H^+ + C2H3O2^-
So (H^+) = 0.02*0.003 = ??
(C2H3O2^-) = 0.02*0.003 = ??
Plug into Ka expression and solve for Ka.
Post your work if you get stuck.

I'm sorry, I don't understand why 0.003 & not 0.03

I got too happy with typing zeros. 3% is 0.03. You're right.

thank you