ABSTRACT
Water molecules act as both acids and bases. One water molecule acting as a base can accept a hydrogen ion from another that acts as an acid. When salts, bases, and gaseous substances enter water, they may dissolve and ionize and interact with the water and any other soluble species that may be present. The extent of these interactions is governed by the principles of chemical equilibrium. The concentration of all the chemical species will appear to be constant. No net change occurs in the amounts of products and reactants. The forward and reverse reactions are operating, but the rates of conversion are equal in both directions. This condition is called equilibrium. pH is a fundamental characteristic of chemical solutions. It determines the extent of ionization of soluble compounds and the formation of solids by ions that tend to precipitate. Low pH indicates acidic conditions.
