Alkalinity Alkalinity Alkalinity is the defined as a body of water's ability to react with the acidic proton. Alkalinity is an important concept in understanding the effects of acid rain.
Alkalinity is different from basicity, which is directly related to the p H .
The higher the p H , the more basic the water. This is called the phenolphthalein alkalinity . At this end point, some of the weaker conjugate bases are protonated. The methyl orange end point titration indicates total alkalinity . In other words, assuming that the alkalinity is due only to the presence of CaCO 3 .