Titrations and Indicators

As in acid-base titrations, indicators and electrodes are commonly used to find the end point of a redox titration. 

Oxazine, azine and thiazine dyes are named for the characteristic heterocyclic ring systems 1,4-oxazine, 1,4-diazine, and 1,4-thiazine. The dyes are generally cationic (basic) or acid dyes. They also can be reduced to colorless forms, then oxidized back to the dye, as in vat dyeing. The dyes also have been used to a limited extent in disperse and fiber reactive applications. They are used as titration indicators and may be applied to acrylic fibers and leather. 

Phenolphthalein, another organic dye (red), is used as an acid-base titration indicator, and also in a laxative [e.g., in Ex-Lax ]. It is in itself sometimes considered to be an anticancer agent. Having the same chemical formula but different structures, the three cresol isomers — ort/to-cresol, meto-cresol, and para-cresol — serve variously as the starting materials for such industrial chemicals as the herbicides DNOC and MCPA, are also used in plastics or resins, and can be converted even to the common food antioxidant known as BHT.)... 

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