0.1 M Edta Solution Standardisation

Suzhoumeite

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Jul 05, 2024

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0.1 M EDTA Solution Standardization

Introduction

EDTA (Ethylene Diamine Tetraacetic Acid) is a versatile chelating agent widely used in various fields, including analytical chemistry, biochemistry, and pharmaceuticals. In analytical chemistry, EDTA is often used as a titrant to determine the concentration of metal ions, such as calcium and magnesium. To ensure the accuracy of the titration results, it is essential to standardize the EDTA solution.

Importance of Standardization

Standardization of the 0.1 M EDTA solution is crucial to ensure the accuracy and reliability of the titration results. EDTA solutions can degrade over time, leading to changes in their concentration. If the EDTA solution is not standardized, it may result in inaccurate determinations of metal ion concentrations, leading to errors in subsequent calculations.

Preparation of 0.1 M EDTA Solution

To prepare a 0.1 M EDTA solution, the following procedure can be followed:

Materials

• EDTA disodium salt (C10H14N2O8S2.2H2O)
• Distilled water
• Sodium hydroxide (NaOH) pellets

Procedure

1. Weigh accurately 3.72 g of EDTA disodium salt and transfer it to a 100 mL beaker.
2. Add approximately 50 mL of distilled water to the beaker and stir until the EDTA is completely dissolved.
3. Add a few NaOH pellets to the solution to adjust the pH to 10-11.
4. Continue stirring until the NaOH pellets are completely dissolved.
5. Transfer the solution to a 100 mL volumetric flask and dilute to the mark with distilled water.
6. Mix well and store the solution in a polyethylene bottle.

Standardization of 0.1 M EDTA Solution

To standardize the 0.1 M EDTA solution, a primary standard calcium carbonate (CaCO3) can be used. The following procedure can be followed:

Materials

• Primary standard calcium carbonate (CaCO3)
• 0.1 M EDTA solution
• Distilled water
• Indicator solution (e.g., Eriochrome Black T or Calcon)

Procedure

1. Weigh accurately 0.1-0.2 g of primary standard calcium carbonate and transfer it to a 250 mL Erlenmeyer flask.
2. Add approximately 50 mL of distilled water to the flask and stir until the calcium carbonate is completely dissolved.
3. Add 1-2 drops of indicator solution to the flask.
4. Titrate the calcium solution with the 0.1 M EDTA solution until the color of the indicator changes.
5. Record the volume of EDTA solution required for the titration.
6. Repeat the titration several times and calculate the average volume of EDTA solution required.
7. Calculate the molarity of the EDTA solution using the following formula:

Molarity of EDTA solution = (Weight of CaCO3 / (Volume of EDTA solution x Molecular weight of CaCO3)) x 1000

Conclusion

In conclusion, standardization of the 0.1 M EDTA solution is a crucial step in ensuring the accuracy and reliability of titration results. By following the procedures outlined above, the EDTA solution can be standardized to determine the concentration of metal ions, such as calcium and magnesium. Regular standardization of the EDTA solution should be performed to maintain its accuracy and reliability.