<P> Alkalinity or A measures the ability of a solution to neutralize acids to the equivalence point of carbonate or bicarbonate . The alkalinity is equal to the stoichiometric sum of the bases in solution . In the natural environment carbonate alkalinity tends to make up most of the total alkalinity due to the common occurrence and dissolution of carbonate rocks and presence of carbon dioxide in the atmosphere . Other common natural components that can contribute to alkalinity include borate, hydroxide, phosphate, silicate, dissolved ammonia, the conjugate bases of some organic acids, and sulfate . Solutions produced in a laboratory may contain a virtually limitless number of bases that contribute to alkalinity . Alkalinity is usually given in the unit mEq / L (milliequivalent per liter). Commercially, as in the swimming pool industry, alkalinity might also be given in parts per million of equivalent calcium carbonate (ppm CaCO). </P> <P> Alkalinity is sometimes incorrectly used interchangeably with basicity . For example, the pH of a solution can be lowered by the addition of CO . This will reduce the basicity; however, the alkalinity will remain unchanged (see example below). For total alkalinity testing N / 10 H2SO4 is used along with phenolphthalein indicator . </P> <P> In typical groundwater or seawater, the measured alkalinity is set equal to: </P> <P> A = (HCO) + 2 (CO) + (B (OH)) + (OH) + 2 (PO) + (HPO) + (SiO (OH)) − (H) − (HSO) </P>

What name is given to the scale that measures acidity and alkalinity