0.1 N Sodium Thiosulfate Pentahydrate Preparation
Introduction
Sodium thiosulfate pentahydrate is a strong reducing agent commonly used in various industrial and laboratory applications, including photography, water treatment, and analytical chemistry. In this article, we will outline the preparation of 0.1 N sodium thiosulfate pentahydrate solution, which is a critical reagent in many analytical procedures.
Materials
- Sodium thiosulfate pentahydrate (Na2S2O3·5H2O)
- Distilled water
Preparation
Step 1: Weighing the Sodium Thiosulfate Pentahydrate
Weigh 24.82 g of sodium thiosulfate pentahydrate (Na2S2O3·5H2O) using an analytical balance.
Step 2: Dissolving the Sodium Thiosulfate Pentahydrate
Transfer the weighed sodium thiosulfate pentahydrate to a 1000 mL volumetric flask.
Add approximately 800 mL of distilled water to the flask and swirl gently to dissolve the sodium thiosulfate pentahydrate.
Step 3: Dilution and Mixing
Dilute the solution to the mark (1000 mL) with distilled water.
Mix the solution thoroughly by inverting the flask several times.
Calculation
The normality of the sodium thiosulfate pentahydrate solution can be calculated using the following formula:
Normality (N) = Molarity (M) x Number of equivalents per mole (n)
For sodium thiosulfate pentahydrate, the molar mass is 248.18 g/mol, and the number of equivalents per mole is 1.
Molarity (M) = moles of Na2S2O3·5H2O / liter of solution = 24.82 g / 248.18 g/mol / 1 L = 0.1 M
Since the number of equivalents per mole is 1, the normality (N) is equal to the molarity (M).
N = M = 0.1 N
Storage and Handling
The prepared 0.1 N sodium thiosulfate pentahydrate solution should be stored in a clean, dry, and dark place to prevent oxidation. It is recommended to store the solution in a glass container with a tight-fitting lid.
Conclusion
In this article, we have outlined the preparation of 0.1 N sodium thiosulfate pentahydrate solution. This solution is a critical reagent in many analytical procedures, and its preparation requires careful attention to detail to ensure the accuracy and reliability of the results.
