Question

A) Calculate the percent ionization of a 0.546 M solution of acetic acid.

% Ionization = ______ % (No K_a value was given)

B) In the laboratory a student measures the percent ionization of a 0.438 M solution of nitrous acid to be 3.31 %.

Calculate value of K_a from this experimental data.  K_a = ______

C) Calculate the percent ionization of a 0.390 M solution of nitrous acid.

% Ionization = ______ % (No K_a value was given)

Answer 1

A)

[H+] = sqrt (Ka x C)

       = sqrt (1.8 x 10^-5 x 0.546)

       = 3.13 x 10^-3 M

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

                    = (3.13 x 10^-3 / 0.546) x 100

% ionization = 0.573 %

B)

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

3.31 = [H+] / 0.438 ) x 100

[H+] = 0.0145 M

Ka = [H+]^2 / C = (0.0145)^2 / 0.438

Ka = 4.80 x 10^-4

C)

Ka = 4.50 x 10^-4

[H+] = 0.0133M

% ionization = 3.40%