0.1M Sodium Thiosulfate Preparation
Introduction
Sodium thiosulfate is a versatile chemical used in various applications, including photographic development, gold extraction, and as an antidote for cyanide poisoning. In laboratory settings, sodium thiosulfate is often used as a reducing agent or to standardize iodine solutions. In this article, we will outline the steps to prepare a 0.1M sodium thiosulfate solution.
Materials Required
- Sodium thiosulfate pentahydrate (Na2S2O3·5H2O)
- Distilled water
- Analytical balance
- 100 mL volumetric flask
- Magnetic stirrer (optional)
Preparation of 0.1M Sodium Thiosulfate Solution
Step 1: Calculate the Amount of Sodium Thiosulfate Required
The molar mass of sodium thiosulfate pentahydrate is 248.18 g/mol. To prepare 100 mL of a 0.1M solution, we need to calculate the amount of sodium thiosulfate required:
moles = Molarity x Volume (L) = 0.1 M x 0.1 L = 0.01 mol
mass = moles x molar mass = 0.01 mol x 248.18 g/mol ≈ 2.482 g
Step 2: Weigh the Sodium Thiosulfate
Using an analytical balance, accurately weigh 2.482 g of sodium thiosulfate pentahydrate.
Step 3: Transfer the Sodium Thiosulfate to a 100 mL Volumetric Flask
Transfer the weighed sodium thiosulfate to a 100 mL volumetric flask.
Step 4: Add Distilled Water
Add approximately 80 mL of distilled water to the flask. You can use a magnetic stirrer to facilitate dissolution, if necessary.
Step 5: Dissolve the Sodium Thiosulfate
Stir the mixture until the sodium thiosulfate is completely dissolved.
Step 6: Dilute to Mark
Add more distilled water to the flask until the 100 mL mark is reached.
Step 7: Mix Well
Mix the solution well to ensure homogeneity.
Storage and Handling
The prepared 0.1M sodium thiosulfate solution should be stored in a cool, dark place. Avoid exposing the solution to direct sunlight or heat, as it may degrade over time. Handle the solution with care, as it can cause skin and eye irritation.
Conclusion
In this article, we have outlined the steps to prepare a 0.1M sodium thiosulfate solution. This solution can be used as a reducing agent or to standardize iodine solutions in laboratory settings. Remember to handle the solution with care and store it properly to maintain its quality and shelf life.
