A complexometric indicator is an ionochromicdye 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 existing outside the complex. Complexometric indicators are also known as pM indicators.[2]
In analytical chemistry, complexometric indicators are used in complexometric titration to indicate the exact moment when all the metal ions in the solution are sequestered by a chelating agent (most usually EDTA). Such indicators are also called metallochromic indicators.
The indicator may be present in another liquid phase in equilibrium with the titrated phase, the indicator is described as extraction indicator.
Some complexometric indicators are sensitive to air and are destroyed. When such solution loses color during titration, a drop or two of fresh indicator may have to be added.
Examplesedit
Complexometric indicators are water-soluble organic molecules. Some examples are:
In some settings, when the titrated system is a redox system whose equilibrium is influenced by the removal of the metal ions, a redox indicator can function as a complexometric indicator.
^M. A. Malati (1999). Experimental Inorganic/Physical Chemistry: An Investigative, Integrated Approach to Practical Project Work (Horwood Series in Chemical Science). Albion/Horwood Pub. p. 20. ISBN1-898563-47-0.
December 15, 2023
complexometric, indicator, complexometric, indicator, ionochromic, that, undergoes, definite, color, change, presence, specific, metal, ions, forms, weak, complex, with, ions, present, solution, which, significantly, different, color, from, form, existing, out. 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 existing outside the complex Complexometric indicators are also known as pM indicators 2 Contents 1 Complexometric titration 2 Examples 3 Redox indicators 4 ReferencesComplexometric titration editIn analytical chemistry complexometric indicators are used in complexometric titration to indicate the exact moment when all the metal ions in the solution are sequestered by a chelating agent most usually EDTA Such indicators are also called metallochromic indicators The indicator may be present in another liquid phase in equilibrium with the titrated phase the indicator is described as extraction indicator Some complexometric indicators are sensitive to air and are destroyed When such solution loses color during titration a drop or two of fresh indicator may have to be added Examples editComplexometric indicators are water soluble organic molecules Some examples are Calcein with EDTA for calcium Patton Reeder Indicator with EDTA for calcium with magnesium Curcumin for boron that forms Rosocyanine although the red color change of curcumin also occurs for pH gt 8 4 Eriochrome Black T for aluminium cadmium zinc calcium and magnesium Fast Sulphon Black with EDTA for copper Hematoxylin for copper Murexide for calcium and rare earths but also for copper nickel cobalt and thorium Xylenol orange for gallium indium and scandiumRedox indicators editIn some settings when the titrated system is a redox system whose equilibrium is influenced by the removal of the metal ions a redox indicator can function as a complexometric indicator References edit Flaschka H Schwarzenbach G Schwarzenbach Gerold 1969 Complexometric titrations London Methuen ISBN 0 416 19290 4 M A Malati 1999 Experimental Inorganic Physical Chemistry An Investigative Integrated Approach to Practical Project Work Horwood Series in Chemical Science Albion Horwood Pub p 20 ISBN 1 898563 47 0 Retrieved from https en wikipedia org w index php title Complexometric indicator amp oldid 1180638138, wikipedia, wiki, book, books, library,
