⚗️ Equilibrium Concentration Calculator
Find the equilibrium concentrations for a weak acid dissociation (HA ⇌ H+ + A-) using an ICE table approach, based on the initial concentration and the acid dissociation constant Ka.
What this calculator finds
This tool solves for equilibrium concentrations in a weak acid dissociation reaction, HA ⇌ H+ + A-, using the classic ICE (Initial, Change, Equilibrium) table method taught in general chemistry.
The method used
Starting from an initial concentration C0 of the weak acid and no products, the change in concentration is represented as x. At equilibrium, [H+] = [A-] = x and [HA] = C0 – x. Substituting into the equilibrium expression Ka = x² / (C0 – x) gives a quadratic equation, which this calculator solves exactly using the quadratic formula rather than the common simplifying assumption that x is negligible compared to C0.
- [H+] and [A-] are equal at equilibrium for a simple monoprotic weak acid.
- pH is calculated from [H+] as -log10[H+].
- Percent dissociation shows how much of the original acid ionized.
This calculator assumes a simple monoprotic weak acid in water with no other equilibria (such as a common ion) present, and is intended for general chemistry education and planning purposes.