Analytical Definition of Alkalinity and Acidity

From these expressions we can see that for systems which are buffered by carbonate species, H+, and OH alone, there is a definite relationship between total alkalinity, pH, and Ct,co3 between total acidity, pH, and Cx.coa- For such systems, if two of these quantities are measured, the third can be calculated. Since many natural waters can be treated as though they were solely buffered by carbonate species, H, and OH , the determination of initial pH and either total alkalinity or total acidity will allow the computation of Ct.co, cti d all species. 

Equivalence Point Reference Species Proton Condition Definition (Alkalinity and Acidity in eq/liter) 

TABLE 4-11 Alkalinity and Acidity in Terms of Cr.coj crnd a Values 

Note If ionic strength effects are important. JC should be used in place of JiTv. and the a values should be calculated using JJ a rather than K.  

What is the total inorganic carbon concentration (in mg carbon/liter) in a water buffered by the carbonate system, and OH The pH on sampling is 7.8 and the water requires 13.7 ml 0.02 N HCl to lower the pH of 100 ml to 4.5. What is the major component of the alkalinity (Neglect ionic strength effects.) 

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