A hydrolysis constant is an equilibrium constant for a hydrolysis reaction.[1]
For example, if a metal salt such as AlCl3 dissolves in an aqueous solution, the metal cation behaves as a Lewis acid and hydrolyzes the water molecules in the solvent.[2]
The hydrolysis constant for this reaction is as shown:
In a more generalized form, the hydrolysis constant can be described as:
where A- represents any base, and HA represents any acid.[3]