Chemical Thermodynamics and the Equilibrium State
Acids and Bases
|One crucially important property of water is its capability to behave as both an acid and a base. Water undergoes autoprotolysis, dissociating to form a positive hydrogen ion and a negative hydroxyl ion.|
In addition to being able to donate a hydrogen ion, water can also receive a hydrogen ion, forming a positive hydronium ion.
In other words, water is amphiprotic. It may donate a hydrogen ion or it may receive one.
Autoprotolysis occurs in equilibrium balance, with the ion product of water, kw, describing the degree to which water will dissociate. An acid or base introduced to the aqueous system will establish a coupled equilibrium with the process of autoprotolysis.