Redox indicator

A redox indicator is a reversible (that is, as often reversible ) redox system, the reduced and oxidized forms are of different colors. A distinction is made between two colored indicators such as ferroin (turning blue - red) and single-color indicators such as methylene blue ( blue envelope - Clear ).

A redox indicator, is to determine the content of a specific oxidizing or reducing agents for use only with certain redox titration. In the redox titration with the strong violet colored potassium permanganate in the Manganometry such an indicator is not required.

A special case is diphenylamine (color change colorless - purple), as a step of dye formation, the benzidine rearrangement is irreversible.