In: Chemistry
Compare the calculated percent ionization of acetic acid in the solution containing both 0.10 M acetic acid and 0.10 M sodium acetate to the calculated percent ionization for the solution containing 0.10 M acetic acid alone. In which solution is the percent ionization the lowest? Clearly and completely explain why this occurs.
Alone acetic acid :
CH3COOH --------------> CH3COO- + H+
0.10 M 0 0
0.10 - x x x
Ka = x^2 / 0.10 - x
1.8 x 10^-5 = x^2 / 0.10 - x
x = 1.34 x 10^-3
% ionization = (1.34 x 10^-3) / 0.1 ) x 100
= 1.34 %
in solution of both
CH3COOH --------------> CH3COO- + H+
0.1 0.10 0
0.10 - x 0.10 + x x
Ka = (0.10 + x) x / (0.10 - x)
1.8 x 10^-5 = (0.10 + x) x / (0.10 - x)
x = 1.8 x 10^-5
% ionization = 1.8 x 10^-5 / 0.1 ) x 100
= 0.018 %
% ionization is lowest in solution containing both acetic acid and sodium acetate