To make a silica standard solution, dissolve sodium metasilicate nonahydrate (Na2SiO3 · 9H2O) in deionized water. Here's a detailed procedure to create a 1000 ppm SiO2 solution:
Procedure for Preparing a 1000 ppm Silica Standard Solution
This procedure outlines how to create a silica standard solution with a concentration of 1000 ppm (parts per million) expressed as SiO2.
Materials:
- Sodium metasilicate nonahydrate (Na2SiO3 · 9H2O)
- Deionized water
- Volumetric flask (1 liter)
- Analytical balance
- Beaker
Steps:
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Weigh the Sodium Metasilicate Nonahydrate: Accurately weigh 4.74 g of Na2SiO3 · 9H2O using an analytical balance.
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Dissolve the Solid: Transfer the weighed Na2SiO3 · 9H2O to a beaker containing approximately 800 ml of deionized water.
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Mix Thoroughly: Stir the solution until the solid is completely dissolved. Ensure no undissolved particles remain.
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Transfer to Volumetric Flask: Carefully transfer the solution to a 1-liter volumetric flask.
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Adjust to Volume: Add deionized water to the flask until the solution reaches the 1-liter mark. Ensure the meniscus is at the calibration line.
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Mix Well: Mix the solution thoroughly by inverting the flask several times.
Result:
The resulting solution is a 1000 ppm silica standard solution, expressed as SiO2.
Important Considerations:
- Purity of Reagents: Use high-purity Na2SiO3 · 9H2O and deionized water to ensure the accuracy of the standard solution.
- Storage: Store the silica standard solution in a clean, tightly sealed container to prevent contamination and evaporation. The solution may degrade over time, so prepare fresh solutions regularly for optimal accuracy.
- Safety: Wear appropriate personal protective equipment (PPE), such as gloves and eye protection, when handling chemicals.
This carefully prepared solution can then be diluted further to create lower concentration standards as needed for your analytical applications.
