Chemistry 102: Acids: concentration

Question

What is the concentration of hydroxide ions for an aqueous solution of acetic acid for which [H₃O⁺] = 2.50 × 10^–4 M ?

Answer 1

The ion-product constant for water is

[H₃O⁺] [OH^-] = 1 x 10¹⁴.

Substituting in the given concentration,

2.50 × 10^–4 [OH^-] = 1 x 10¹⁴,

and now it's a simple matter to solve for the concentration of hydroxide ions [OH^-]