At 25 degrees Celsius the Ka for a 0.120 mol/L solution of acetic acid (HC2H3O2 ) is 1.8 X 10-5. determine the pH of the acetic acid solution

HC2H3O2 ==> H^+ C2H3O2^-

Ka = (H^+)(C2H3O2^-)/(HC2H3O2).
Set up an ICE chart, substitute into the above Ka expression, and solve for H^+, then convert to pH. Post your work if you get stuck.