How do you standardize EDTA with CaCO3?

0.01M EDTA standardization against calcium carbonate

1. Weight exactly about 1g of dry calcium carbonate.
2. Dissolve solid in 25 mL of 1M HCl solution and dilute in volumetric flask to exactly 1L.
3. Transfer 25 mL of calcium solution to Erlenmeyer flask.
4. Add 75 mL of distilled water.
5. Add 10 mL of 1M sodium hydroxide solution.

How do you standardize EDTA solution?

Primary standard calcium carbonate can be used to standardize EDTA solutions. Of the various EDTA species, only the Y4-‐ ion (the completely deprotonated anion of EDTA) forms a 1:1 complex with metal ions. To increase the fraction of Y4-‐, the pH needs to be increased to 10 in this experiment.

How does EDTA react with calcium?

As a result, when the calcium ion–PR complex is titrated with EDTA the Ca2+ ions react to form a stronger complex with the EDTA. For the titration, the indicator is added to the sample solution containing the calcium ions and forms the pink/red calcium ion-indicator complex (Ca-PR).

What is the molar ratio of EDTA to CaCO3?

Each mL EDTA used = 0.00002 equivalents: 0.001 L x 0.02 equivalent EDTA/L = 0.00002 equivalent EDTA = equivalent CaCO3. Each mL EDTA used = 0.00001 moles CaCO3:0.001 L x 0.01 mol EDTA/L = 0.00001 moles EDTA = moles Ca or CaCO3.

What is standardization of EDTA?

In this procedure a stock solution of EDTA will be standardized against primary standard CaCO3. This standardized EDTA solution is then used to determine water “hardness” – the total calcium and magnesium content, typically expressed as equivalent calcium carbonate mass concentration.

Why we standardize the EDTA solution?

Since [Metal ion]+ is unknown, you can make no measurement of the amount present, unless you know [EDTA] fairly accurately. And thus a known mass of primary standard is required to standardize, to calibrate the titration.

How do you calculate hardness of water using EDTA titration?

The total hardness of water is estimated by titrating the water sample against EDTA using Eriochrome Black-T (EBT) indicator. Initially EBT forms a weak EBT- Ca2+/Mg2+ wine red coloured complex with Ca2+/Mg2+ ions present in the hard water.

How do you calculate CaCO3?

Molar mass (CaCO3) = M(Ca) + M(C) + 3 x M(O) = 40 + 12 + 3 x 16 = 100 g/mole. Divide the molar mass by the ion charge or oxidation number (for CaCO3) to determine equivalent (Eq.) weights.

Why Standard EDTA is standardized with standard hard water?

Why is EDTA a secondary standard solution?

Unfortunately EDTA cannot be easily used as a primary standard. The H4Y form can be dried at 140◦C for 2 hrs and used as a primary standard, but is only sparingly soluble in water.

Why do we do standardization of solution?

The so-called titer determination or standardization of a volumetric solution used for titration is one of the most important preconditions for reliable and transparent titration results. Accurate and reliable titration results are only achievable when we work with the exact concentration of the volumetric solution.

How is calcium carbonate dissolved in EDTA solution?

Pure Calcium Carbonate is dissolved by adding a slight excess of HCl. This solution is then quantitatively transferred to a 100 mL volumetric flask, diluted to volume and mixed thoroughly. This standard calcium solution, of known concentration, is used to determine the exact concentration of the EDTA solution.

Which is the molarity of EDTA for CaCO3?

Molarity of EDTA == 0.0149 M EDTA0.02725L 3. Ca2+concentration in an unknown solution CaCO3reported as ppm CaCO3. 50.00 mL unknown solution requires25.55 ml of the standardized EDTA solution forcomplete reaction. What is the Ca2+concentration in the unknown reported as ppm CaCO3?

Is there standardization of EDTA solution for use in complexometric?

For best results it is good to standardize EDTA solution against the same cation and using the same method as will be later used during sample analysis. Note, that EDTA solution can be prepared without a need for standardization, as EDTA itself can be obtained in form pure enough. Titration is done in pH 10 solution.

How to dilute HCl solution with EDTA solution?

Weight exactly about 0.24g of metallic Mg ribbon. Dissolve metal in 25 mL of 1M HCl solution and dilute in volumetric flask to exactly 1L. Transfer 25 mL of magnesium solution to Erlenmeyer flask. Add 75 mL of distilled water.