How do you calculate EDTA concentration from titration?

How do you calculate EDTA concentration from titration?

Calculate the concentration of calcium ions in the hard water sample.

1. Calculate the average titre of EDTA: average titre = (8.76 + 8.80 + 8.78) ÷ 3 = 8.78 mL = 8.78 x 10-3 L.
2. Calculate the moles of EDTA in the average titre: moles(EDTA) = concentration (mol L-1) x volume (L) = 0.010 x 8.78 x 10-3 = 8.78 x 10-5 mol.

What is the end point indication for EDTA titration for hardness estimation?

Estimation of Permanent Hardness 20 ml of the made up solution is pipetted out into a conical flask, 5 ml ammonia buffer and 2 drops of EBT indicator are added and titrated against the EDTA. The end point is the change of colour from wine red to steel blue. The titration is repeated to get concordant titre value.

What is the end point of titration in EDTA method?

Indicators. Calmagite and Eriochrome BlackT (EBT) are such indicators that change from blue to pink when they complex with calcium or magnesium. The endpoint of a complexometric EDTA titration using either Calmagite or EBT as the indicator is detected as the colour changes from pink to blue.

How is EDTA water hardness calculated?

The estimation of hardness is based on complexometric titration. 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.

How do you do EDTA titration?

Titration Procedure Titrate with EDTA from violet through wine-red to blue. It is recommended to experiment with a 5 mL aliquot to get an idea of the color and titre. The indicator color changes slowly, thus, the titrant must be added slowly near the endpoint with thorough stirring. Calculate the molarity of the EDTA.

Why do we use EDTA in titration to calculate hardness?

In the determination of water hardness, ethylene- diaminetetraacetic acid (EDTA) is used as the titrant that complexes Ca2+ and Mg2+ ions. This color change signals the end point, as it takes place when the EDTA, after complexing all of the unbound Ca2+ and Mg2+ ions, removes the Mg2+ ion bound to the indicator.

What does the coordination number mean in complexometric titrations?

The number of complexes any cation tends to form with the electron donors (ligands) is referred to as its coordination number. Source: Titration with formation of complexes.

How does EDTA titration work?

EDTA is short for ethylenediaminetetraacetic acid. For the titration, the sample solution containing the calcium and magnesium ions is reacted with an excess of EDTA. The indicator is added and remains blue as all the Ca2+ and Mg2+ ions present are complexed with the EDTA.

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 remain free in the sample and solution turns blue.

How do you calculate total water hardness?

The amount of hardness is expressed in milligrams per litre (mg/L) or grains per gallon (gpg) as calcium carbonate. Hardness is calculated from the equation Hardness = 2.497 (Ca) + 4.118 (Mg).

What type of titration is EDTA titration?

Direct titration: the cations are titrated directly with standard solution EDTA using eriochrome black T as the indicator. Back titration: a known excess of standard solution EDTA is added to the solution containing the analyte.

What is the use of EDTA in titration?

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.

What is the end point of EDTA titration?

In a titration to establish the concentration of a metal ion, the EDTA that is added combines quantitatively with the cation to form the complex. The end point occurs when essentially all of the cation has reacted. In this experiment you will standardize a solution of EDTA by titration against a standard solution made from calcium carbonate, CaCO3.

How is the hardness of water determined by EDTA?

EDTA Titration Calculations The hardness of water is due in part to the presence of Ca2+ions in water. Theconcentration of Ca2+ions is usually expressed as ppm CaCO3in the water sample. Thisis equivalent to 1 gram of CaCO3in 106grams of sample. In the lab 1 ppm CaCO3isexpressed as 1 mg CaCO3per 1 Liter of sample or ppm is mg CaCO3per L of sample.

What do you call a titration based on complex formation?

A titration based on complex formation is called a complexometric titration. Ligands other than NTA form strong 1:1 complexes with all metal ions except univalent ions such as Li+, Na+ and K+. The stoichiometry is 1:1 regardless of the charge on the ion.

What is the conditional formation constant for EDTA?

Conditional Formation Constant. The formation constant Kf = [MYn − 4]/[Mn+][Y4−] describes the reaction between Y4− and a metal ion. As seen in the fractional composition diagram, most EDTA is not Y4− below pH 10.37. The species HY3−, H2Y2−, and so on, predominate at lower pH.