Question

Determine the percent ionization of the following solutions of phenol at 25 degrees C.

a) 0.591M

b)0.430M

c) 1.40x10^-6M

Answer 1

a )

Ka of phenol = 1.3×10^–10

concentration C = 0.591 M

[H+] = sqrt (Ka x C) = sqrt (1.3 x 10^-10 x 0.591)

        = 8.76 x 10^-6 M

% ionization = ([H+] / C ) x 100

                    = (8.76 x 10^-6 / 0.591 ) x 100

                   = 0.00148 %

b)

[H+] = sqrt (Ka x C) = sqrt (1.3 x 10^-10 x 0.430)

        = 7.48 x 10^-6 M

% ionization = ([H+] / C ) x 100

                    = (7.48 x 10^-6 / 0.430 ) x 100

% ionization = 0.00174 %

c)

% ionization = 0.964 %