You can calculate the acid dissociation constant of a weak acid from experimental data

The generic equilibrium constant expression for a weak acid is written as follows.

If the acid is strong enough to ignore the dissociation of water, the H3O+ ion and A- ion concentrations in this solution are about equal.

[H3O+]  [A-]

Substituting this information into the acid-dissociation equilibrium constant expression gives the following result.

The concentration of the HA molecules at equilibrium is equal to the initial concentration of the acid minus the amount that dissociates: C.

If C is small compared with the initial concentration of the acid, we get the following approximate equation.

Rearranging this equation and taking the square root of both sides gives the following result.

no

Explanation: just because of life