The general equilibrium expression for an acid, often denoted as Ka (acid dissociation constant), is:
Ka = [H+][A-] / [HA]
Where:
- Ka is the acid dissociation constant.
- [H+] is the concentration of hydrogen ions (protons) in the solution.
- [A-] is the concentration of the conjugate base of the acid.
- [HA] is the concentration of the undissociated or unionized acid.
This expression describes the extent to which an acid (HA) dissociates or ionizes in a solution, forming hydrogen ions (H+) and its conjugate base (A-). A higher Ka value indicates a stronger acid because it dissociates more readily, leading to higher concentrations of H+ ions and A- ions in the solution.