Why disodium salt of EDTA is used instead of EDTA in complexometric titration?
The disodium salt of EDTA is preferred in hardness estimation mainly because it is more soluble in aqueous solutions which allows release of the EDTA ligand into solution to react.
Why only the disodium salt of EDTA is always used in the complexometric titrations of metal ions?
Disodium EDTA (often written as Na2H2Y) only forms four coordinate covalent bonds to metal cations at pH values ≤ 12. For most purposes it can be considered that the formation of the metal cation-EDTA complex goes to completion, and this is chiefly why EDTA is used in titrations and standardizations of this type.
What is the difference between EDTA and EDTA disodium salt?
EDTA is Ethylene Diamine Tetra Acetic acid. EDTA is a tetrabasic acid. It is essentially insoluble in water. The disodium salt is soluble in water at room temperature up to a concentration of 0.26 mol/L.
Why do we use Na2EDTA instead of EDTA?
Na2EDTA is EDTA, disodium salt dihydrate. Since it has two molecules of water, it should be easier to dissolve in water than anhydrous form.
Why is sodium salt used in EDTA?
For use as an anticoagulant, disodium or tripotassium salts of EDTA are most commonly used. EDTA prevents platelet aggregation and is therefore the preferred anticoagulant for platelet counts. 3 From a 2\% EDTA solution, 1-2 drops per ml of whole blood can be used as an anticoagulant.
Why basic condition is required for EDTA titration?
The carboxyl groups of EDTA are not dissociated at low pH. Undissociated carboxyls (COOH) have no charge because the hydrogen is covalently bound and therefore acid EDTA is almost insoluble in water. You may use Na-EDTA, which is soluble salt. Dissociated EDTA is ionic and thus water soluble.
Why is sodium salt of EDTA used generally?
For use as an anticoagulant, disodium or tripotassium salts of EDTA are most commonly used. The optimal concentration is 1.5 mg per ml of blood. EDTA prevents platelet aggregation and is therefore the preferred anticoagulant for platelet counts.
Why EDTA itself is not used in complexometric titration?
Their main disadvantages are that they have low sensitivity and selectivity. Ethylenediaminetetraacetic acid (EDTA) complexometric titrations are based on the fact that many metallic ions form stable complexes with this tetradentate ligand, EDTA.
What is EDTA for titration purpose only disodium salt is used Why?
The Disodium salt of EDTA is the most commonly used form of this versatile organic complexing agent, which is used for the determination of many metal ions either by direct titration or by back-titration. The last addition of EDTA then removes the metal ion from its complex with the indicator, producing a color change.
Can I use EDTA instead of disodium EDTA?
Disodium EDTA has a molecular weight of 336.2 g/mol. The differences are the solubility and the pH of the resulting solution. Although If you will add NaOH to your buffer, the chemical composition of the resulting buffer will be the same in case of using both. Kind regards.
Is disodium EDTA salt?
An organic sodium salt that is the anhydrous form of the disodium salt of ethylenediaminetetraacetic acid (EDTA)….CHEBI:64734.
| Synonyms | Sources |
|---|---|
| ethylenediaminetetraacetic acid disodium salt | SUBMITTER |
| N,N’-1,2-ethanediylbis[N-(carboxymethyl)glycine], disodium salt | ChEBI |
| Na2-EDTA | ChEBI |
Why disodium salt of EDTA is normally used for titration of water?
Hardness of water is determined by titrating with a standard solution of ethylene diamine tetra acetic acid (EDTA) which is a complexing agent. Since EDTA is insoluble in water, the disodium salt of EDTA is taken for this experiment. Why disodium salt of EDTA is normally used for preparing standard solution of EDTA?
Why does EDTA not form a complex with sodium?
High ionic radius and hardness of alkali and alkaline earth metal ions against the soft carboxylate make chelation less favourable with respect to softer metal ions, such as group III metals and transition metals. Hence EDTA doesn’t form a complex with sodium but forms a salt.
What is the titration of CaCA2+ + EDTA4-?
Ca 2+ + EDTA 4- → CaEDTA 2- Titration is done in about 0.1 sodium hydroxide solution (pH around 13). While this is not our intent when standardizing EDTA solution, at this high pH it is possible to titrate calcium in the presence of magnesium as the latter precipitates in the form of Mg (OH) 2.
What happens when all metal ions are bound to 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 remain free in the sample and solution turns blue. We can write complex forming ion of EDTA as H2Y2- which it forms in aqueous solution. The reactions of it with metal ions can be written as follows –