a)
butanoic acid ---------------> butanoate + H+
0.00710Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
0Â Â Â Â Â Â Â Â Â Â Â Â
0
0.00710 -
x                           Â
x            Â
x
Ka = x^2 / 0.00710 - x
1.5 x 10^-5 = x^2 / 0.00710 - x
x = 3.19 x 10^-4
[H+] = 3.19 x 10^-4 M
% ionization = (3.19 x 10^-4 / 0.00710 ) x 100
% ionization = 4.49 %
b)
HA -------------> A- + H+
Ka = [A-][H+] / [HA]
1.5 x 10^-5 = [0.0210][H+] / 0.00710
[H+] = 5.07 x 10^-6 M
% ionization = (5.07 x 10^-6 / 0.0071 ) x 100
% ionization = 0.0714 %
