Redox indicator

Redox indicator

A redox indicator (also called an oxidation-reduction indicator) is an indicator that undergoes a definite color change at a specific electrode potential.

The requirement for fast and reversible color change means that the oxidation-reduction equilibrium for an indicator redox system needs to be established very fast. Therefore only a few classes of organic redox systems can be used for indicator purposes.

There are two common type of redox indicators:
* metal-organic complexes (Ex. phenanthroline)
* true organic redox systems (Ex. Methylene blue) Sometimes colored inorganic oxidants or reductants (Ex. Potassium manganate, Potassium dichromate) are also incorrectly called redox indicators. They can’t be classified as true redox indicators because of their irreversibility.

Almost all redox indicators with true organic redox systems involve a proton as a participant in their electrochemical reaction. Therefore sometimes redox indicators are also divided into two general groups: independent or dependent on pH.

pH independent redox indicators

pH dependent redox indicators

ee also

*pH indicator


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • redox indicator — oksidacinis redukcinis indikatorius statusas T sritis Standartizacija ir metrologija apibrėžtis Medžiaga, kurios spalva priklauso nuo oksidacijos redukcijos potencialo vertės. atitikmenys: angl. redox indicator vok. Redoxindikator, m rus.… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • redox indicator — oksidacinis redukcinis indikatorius statusas T sritis chemija apibrėžtis Medžiaga, keičianti spalvą priklausomai nuo oksidacijos redukcijos potencialo dydžio. atitikmenys: angl. redox indicator rus. окислительно восстановительный индикатор;… …   Chemijos terminų aiškinamasis žodynas

  • redox indicator — a pigment which indicates by a change of color a change in the oxidation potential …   Medical dictionary

  • Redox titration — (also called oxidation reduction titration) is a type of titration based on a redox reaction between the analyte and titrant.Redox titration may involve the use of a redox indicator and/or a potentiometer.ExampleAn example of a redox titration is …   Wikipedia

  • Indicator — may mean:* pH indicator, a chemical detector for protons in acid base titrations * Redox indicator, a chemical detector for redox titrations * Complexometric indicator, a chemical detector for metal ions in complexometric titrations * Zeta… …   Wikipedia

  • indicator — 1. In chemical analysis, a substance that changes color within a certain definite range of pH or oxidation potential, or in any way renders visible the completion of a chemical reaction; e.g., litmus, phenolsulfonphthalein. 2 …   Medical dictionary

  • Complexometric indicator — A complexometric indicator is an ionochromic dye that undergoes a definite color change in presence of specific metal ions.[1] It forms a weak complex with the ions present in the solution, which has a significantly different color from the form… …   Wikipedia

  • indicateur redox — oksidacinis redukcinis indikatorius statusas T sritis Standartizacija ir metrologija apibrėžtis Medžiaga, kurios spalva priklauso nuo oksidacijos redukcijos potencialo vertės. atitikmenys: angl. redox indicator vok. Redoxindikator, m rus.… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • pH indicator — Acids and Bases Acid dissociation constant Acid base extraction Acid–base reaction Acid–base titration Dissociation constant Acidity function Buffer sol …   Wikipedia

  • Starch indicator — Starch is often used in chemistry as an indicator for redox titrations where iodine is present. Starch forms a very dark blue black complex with iodine. The indicator is not affected by the presence of iodide (I ). Starch indicator solutions may… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”