Direct Titrations of Acid Compounds

We choose to comment on examples for which equivalence points are detected with the help of color indicators or of pH-metry. For now, it is sufficient to know that pH-metry is a method that indicates the equivalence point and that it is more precise than methods using neutralization indicators. 

Acid compounds are usually titrated with sodium or potassium hydroxide solutions. Apart from some mineral compounds, the othCT compounds titrated are essentially carboxylic acids, phenols, imides, and quaternary ammoniums resulting from the protonation of amines. 

Among the mineral compounds, we d like to mention the titration of the sodium dihydrogen phosphate. It is performed in the presence of phenolphthalein according 

Numerous titrations of carboxylic acids have been proposed in the literature, in strictly aqueous solutions as well as in hydro-organic mixtures. Among those reported in strictly aqueous solutions are the titrations of maleic, malic, tartaric, citric, and sorbic acids (Fig. 11.1). Their equivalence points are detected with phenolphthalein. All of them, including the polyacids just listed, exhibit only one endpoint. The endpoint color change is detected for the titration stage at which the number of added equivalents of sodium hydroxide is equal to the number of acid functions the titrand possesses. We d like to point out the following facts about these titrations  

A somewhat different case is that of the a-amino acids, which contain a supplementary carboxylic group in their structure. Two examples are provided, for example, by aspartic and glutamic acids. 

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