Introduction

Ethylenedinitrilotetraacetic acid (EDTA), specifically the disodium salt dihydrate, is a chelating agent commonly used in biochemistry, analytical chemistry, and pharmaceutical industries for its ability to bind to metal ions. This article provides a comprehensive guide on how to prepare 10 liters of a 0.05 mM EDTA solution, detailing the necessary calculations and steps involved.

Understanding Molarity and Concentration

Molarity (M) is defined as the number of moles of solute per liter of solution. Given that we aim to create a 0.05 mM (millimolar) solution, we need to first convert this concentration to moles per liter (mM millimoles per liter).

Calculating the Required Amount of EDTA

The formula to calculate the amount of solute needed for a desired concentration is:

Amount (g) Concentration (mmol/L) × Volume (L) × Molar Mass (g/mol)

Step 1: Convert the desired concentration to millimoles per liter:

0.05 mM 0.05 mmol/L

Step 2: Multiply by the volume of the solution:

Volume (L) 10 L

Step 3: Find the molar mass of EDTA:

The molar mass of EDTA, disodium salt (Na2H2Y·2H2O), is approximately 372.2438 g/mol. However, the problem states a different molar mass, 292.2438 g/mol, which might refer to a slightly different compound or a potential error. For this guide, we will use the given value.

Step 4: Perform the calculation:

Amount (g) 0.05 mmol/L × 10 L × 292.2438 g/mol

Amount (g) 0.5 mmol × 292.2438 g/mol 146.1219 g

Step 5: Double-check using a calculator:

0.05 × 10 × 292.2438 146.1219 g

Preparation Procedure

Step 1: Weigh the Proper Amount of EDTA

Weigh out 146.1219 grams of EDTA disodium salt dihydrate using an analytical balance to ensure accuracy.

Step 2: Prepare the Solution

Mix the precisely measured EDTA and a sufficient volume of distilled or deionized water in a clean container.

Step 3: Dilute to Volume

Add distilled or deionized water until the total volume reaches 10 liters. This can be achieved using a volumetric flask or a graduated cylinder.

Step 4: Stir the Solution

Sufficiently stir the solution to ensure complete and uniform dissolution of the EDTA.

Step 5: Label and Store the Solution

Label the prepared solution with the concentration, preparation date, and any necessary additional information. Store it in a cool, dry place or refrigerator to maintain its stability.

Conclusion

Preparation of a 0.05 mM EDTA disodium salt dihydrate solution is a straightforward process once the correct calculations and procedure are followed. By accurately weighing and dissolving the compound in the correct volume of water, you can reliably prepare this essential reagent for your laboratory or industrial needs.

FAQs

Q: What is the molar mass of EDTA disodium salt dihydrate?

A: The molar mass of EDTA disodium salt dihydrate is approximately 372.2438 g/mol. However, the problem provided a different value of 292.2438 g/mol. This discrepancy could be due to a different compound or miscalculation.

Q: How accurate does the weighing need to be?

A: For precise laboratory work, it is crucial to use a high-accuracy analytical balance to weigh the EDTA. The amount should be accurate to at least 0.001 g to ensure the concentration is as specified.

Q: What is the purpose of using distilled or deionized water?

A: Using distilled or deionized water ensures that no impurities are introduced into the solution, which could affect the purity of the final EDTA solution.