In: Chemistry
(a) Calculate the percent ionization of 0.00690 M hypochlorous acid (Ka = 3e-08). % ionization =
(b) Calculate the percent ionization of 0.00690 M hypochlorous acid in a solution containing 0.0300 M sodium hypochlorite. % ionization =
a)
concentration of hypochlorous acid = C = 0.00690 M
[H+] = sqrt (Ka x C)
= sqrt (3 x 10^-8 x 0.00690)
= 1.438 x 10^-5 M
% ionization = ([H+] / C ) x 100
= (1.438 x 10^-5 / 0.00690 ) x 100
% ionization = 0.208 %
b)
ClO- + H2O ------------> HClO + OH-
0.03 0.00690 0
0.03 - x 0.00690 + x x
Kb = (x)(0.00690-x) / (0.03 - x)
3.33 x 10^-7 = 0.00690x - x^2 / 0.03 - x
x = 6.898 x 10^-3
[OH-] = 6.898 x 10^-3 M
% ionization = (6.898 x 10^-3 / 0.03 ) x 100
% ionization = 23.0 %