Chemistry: What is A Complexometric Titration

Introduction:
According to (Khan): A complexometric titration as defined by IUPAC as a volumetric titration where a soluble complex can be formed by titrating a metal ion with a ligand in an aqueous solution and a titrant is one of the reacts used in the titration. [4]
M(H2O)n + L = M(H2O)(n-1)L + H20 [4]
(Khan): further states, here L are the Ligand and which is formed via the complete replacement of water molecules by other ligands can occur till the formation of the MLn complex. “n” is the coordination number of the metal ion and represents the maximum number of monodentate ligands which can be bound to it [8]

Figure 1: The hexacyanoferrate iron (III) ion: contains 6 ligands which are bound to the central metal therefore has a coordination number of 6 (n=6¬). (Hussain,2007) [13]

A complexometric titration takes place in an aqueous sample inorder to displace water from the ion. As the metal ion will be ionated once in solution therefore, empty valence empty shells are achieved [1]

According to (Biesen) , In a complexometric titration a coordination covalent bond is formed via the ability of most metal ions to receive unshared pairs of electrons from a anion or molecule. Furthermore, a ligand: which is a molecule that contain a lone pair of electrons and can therefore form a bond with a complex ion or metal ion. Therefore a ligand determines the metal ion concentration. [2] Therefore according to (Hussain, 2007), the maximum amount of ligands that can take part in a titration are known as Werner’s Number and allow for complex formation.[13]

A complexometric titration is based upon the following equations:

Figure 2 : Adapted from (Huss...

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...ble from: https://www.bhsu.edu/Portals/91/AnalyticalChemistry/StudyHelp/LectureNotes/Chapter13.pdf
Complexometric Titrations [homepage on the internet]. No date. [ cited 2014 Mar 20]. Available from: http://www.ciens.ucv.ve:8080/generador/sites/martinezma/archivos/EDTA.pdf
Gusdinar T. COMPLEXOMETRIC TITRATION An application method of Inorganic Pharmaceutical Analysis [homepage on the internet] . No date. [cited 2014 Mar 20]. Available from: http://download.fa.itb.ac.id/filenya/Handout%20Kuliah/Inorganic%20Pharmaceutical%20Analysis%202008/English%20Version/05.%20COMPLEXOMETRIC%20TITRATION.pdf.
EDTA Titrations [homepage on the internet]. No date. [cited 2014 Mar 24]. Available from: http://bionmr.unl.edu/courses/chem221/lectures/chapter-12.ppt. https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSr8T9O08hjWT4n_LqSRWKxWaoPh8aUOpDzzdys1C3bMGVeAY9o Aooendix a and b