Question

What is the pH and the degree of dissociation in a a) 0.1 M; in a b) 0.01 M and in a c) 0.001 M acetic acid solution, respectively?

Answer 1

(a) Acetic acid is a weak acid, so: 

However, if the c_{weak acid} = 0.1 M, we can use the simpler form of the formula: 

= 2.865

(c) Here again we do not have enough difference in the order of magnitude to 

= 3.904

 In this case [H⁺ ] = [acetate ion],

= 12.7%