Conditions That Must be Fulfilled for Satisfactory Titrations

5 Conditions That Must be Fulfilled for Satisfactory Titrations 

The titration of a weak acid with a strong base will be satisfactory only in some concentration conditions, depending on the strength of the acid. The parameter that is conditional for the success of the titration is p, which, in the present case (see Chap. 10), is defined by 

We note that both parameters Ka and Co are linked in the expression of p. We accept that the titration is satisfactory when p 10 . This value has been derived experimentally. It means that for higher values, the equivalence point can no longer be satisfactorily detected (see the following chapter). The parameter rationalizes some experimental facts. For example, it indicates that the titrations with a strong base of orthoboric acid (pKa = 9.10) and the ammonium ion pKa = 9.24) (both 10 mol/L) cannot be satisfactory. At first sight, we can consider that the greater the difference is between the pKa value and the acidity scale limit (14), the more satisfactory the titration of a weak acid by a strong base will be. In other words, the couple HA/A must be located as far as possible from the couple H20/0H on the acidity scale. 

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