What is the principle of complexometric titration with EDTA?
Eriochrome Black T binds with metal ions loosely while EDTA binds with metal ions strongly. So, when all metal ions are bound to EDTA, indicator EBT remains free in the sample and the solution turns blue.
How does EDTA determine metal ions?
As the EDTA titrant is added to a hard water sample, free Mg2+ and Ca2+ ions are captured first. After complex- ation of all the free ions, EDTA reacts with the small amount of bound metal ion–indicator complex. The metal ions are effectively removed from the indicator as EDTA binds more tightly to these ions.
What is the principle of complexometric titration?
Complexometric titration is a form of volumetric titration in which the formation of a colored complex is used to indicate the end point of a titration. The complexes are formed by the reaction of a metal ion (an acceptor, a central atom or a cation) with an anion, a neutral molecule or very rarely a positive ion.
What are the advantages of using EDTA in the complexometric titrations?
EDTA or Ethylenediaminetetraacetic acid is commonly used as an indicator for complexometric titration because it can act as a ligand which can bind to coordinate centers which are usually metals to form colored complexes.
What are the advantages of complexometric titration?
Complexometric titrations are particularly useful for the determination of a mixture of different metal ions in solution. An indicator capable of producing an unambiguous color change is usually used to detect the end-point of the titration.
Why is EDTA used in complexometric titrations?
The most common indicators in complexometric titrations are organic dyes which function by forming a colored complex with the metal ion being titrated. During the reaction, EDTA replaces the indicator to form a more stable complex with metal and when the reaction is completed the change for the color is observed.
Why EBT is used in complexometric titration?
Eriochrome black T is used as an indicator for complexometric titrations because it forms a colored complex in its protonated form with calcium,… See full answer below.
Why we use EBT indicator in complexometric titration?
Why complexometric titrations are pH dependent?
The strength and stability of EDTA complexes depends mainly on the pH. The number of electron pairs actually available to form coordination bonds depends on the dissociation levels of the acid groups and therefore the pH.
What are the disadvantages of complexometric titration?
It is a destructive method as it use relatively large quantities of the substance being analysed. It can produce chemical waste which has to be then disposed of. It has limited accuracy. There is a chance of human error by this method.
Why EDTA is stable than EBT?
Answer. EDTA is insoluble in water at low pH because H4Y is predominant in that pH (less than 2). With increasing the pH, each hydrogen ion in the carboxyl groups of EDTA will start to dissociate. Above pH 10, Y4- is predominant.
What are the 4 types of titration?
Types of Titration
- Acid-base Titrations.
- Redox Titrations.
- Precipitation Titrations.
- Complexometric Titrations.