Equilibrium constant
![](/Images/godic/202412/20/Micro_constants5242.png")
![Variation of log Kc of acetic acid with ionic strength](/Images/godic/202412/20/PK_acetic_acid5242.png")
![Pressure dependence of the water ionization constant at 25 °C. In general, ionization in aqueous solutions tends to increase with increasing pressure.](/Images/godic/202412/20/Pressure_dependence_water_ionization_pKw_on_P.svg5242.png")
The equilibrium constant of a chemical reaction is the value of the reaction quotient when the reaction has reached equilibrium. An equilibrium constant value is independent of the analytical concentrations of the reactant and product species in a mixture, but depends on temperature and on ionic strength. Known equilibrium constant values can be used to determine the composition of a system at equilibrium.