What is EDTA titration method?

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 is EDTA used for 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 are the types of EDTA titration?

Types of titration with EDTA 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 does EDTA test for in water?

Calcium and magnesium salts dissolved in water cause water hardness. Water hardness can be measured using a titration with ethylenediaminetetraacetic acid (EDTA).

Why is EDTA used to determine the hardness 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. EDTA can form four or six coordination bonds with a metal ion.

How many titration methods are used for EDTA?

two methods
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. The endpoint detection in complexometric titration can be done by two methods.

How is EDTA calculated?

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.

How to standardize EDTA?

Weigh accurately about 400 mg of Calcium Carbonate.

  • Previously dried at about 110°C for about 2 hours.
  • Transfer it in a cleaned and dried 500 ml conical flask and add about 10 ml of water with gentle stirring to form the slurry.
  • Dissolve the carbonate in 2 ml of dilute hydrochloric acid and shake well until it dissolves.
  • EDTA (aq)+NH3 buffer+EBT indicator+Ca++/Mg++= EDTA complex with Ca++/Mg++(either/or)

  • Ca++and/or Mg++complexes with EDTA,going from pink to blue in the presence of Erichrome Black-T and buffer,when no Mg++or Ca++remain uncomplexed.
  • So (18.25ml/50.00ml) x 0.00940M = 0.003431mole of EDTA
  • The Ca/Mg is usually reported as ppm CaCO3
  • Why magnesium nitrate is added to EDTA titration?

    titration. As EDTA is added, it will complex free Ca2+ and Mg2+ ions leaving the MgIn-complex alone until essentially all of the calcium and magnesium has been converted to chelates. At this point, the EDTA concentration will increase sufficiently to displace Mg2+ from the indicator

    What is the principle of EDTA titration?

    Take 25ml of given sample in conical flask.

  • Now add 1ml of buffer solution.
  • Now in sample and buffer solution add 1ml of inhibitor as well.
  • Now add 2 drops of eriochrome black – T solution in the mixture which turns the color of the solution wine red.
  • Fill the burette with EDTA solution.
  • End point can be detected by color change from wine red to blue.