The acid dissociation constant is 1.3 × 10^-3.
<h3>What is acid-dissociation constant?</h3>
The acid-dissociation constant is a constant that shows the extent of dissociation of an acid in solution. We have to set up the reaction equation as shown below;
Let the acid be HA;
HA + H2O ⇄ H3O^+ + A^-
since the pH of the solution is 2.57 then;
[H3O^+] = Antilog(-pH) = Antilog(-2.57) = 2.7 × 10^-3
We can see that; [H3O^+] = [A^-] so;
Ka = (2.7 × 10^-3)^2/(5.5 × 10^–3)
Ka = 1.3 × 10^-3
Learn more about acid-dissociation constant: brainly.com/question/9728159
