How to Make Calcium Standard Solution?

To make a 0.1M Calcium Chloride (CaCl₂) standard solution, dissolve 14.7 grams of reagent-grade calcium chloride dihydrate (CaCl₂ · 2H₂O) in distilled water and dilute to 1 liter. Here’s a step-by-step guide:

Steps to Prepare a 0.1M Calcium Chloride (CaCl₂) Standard Solution:

1. Gather Materials: You'll need the following:

   • Reagent-grade calcium chloride dihydrate (CaCl₂ · 2H₂O)
   • Distilled water
   • A 1-liter volumetric flask
   • A weighing balance
   • A spatula
   • A funnel (optional)
   • A wash bottle

2. Calculate the Required Mass: For a 0.1M CaCl₂ solution using calcium chloride dihydrate (CaCl₂ · 2H₂O), you need to dissolve 14.7 grams in 1 liter of solution.

   • Rationale: The molecular weight of CaCl₂ · 2H₂O is approximately 147 g/mol. To make a 0.1M solution in a 1-liter volume, you need 0.1 moles of CaCl₂ · 2H₂O, which is equivalent to 0.1 moles * 147 g/mol = 14.7 grams.

3. Weigh the Calcium Chloride Dihydrate: Carefully weigh out 14.7 grams of CaCl₂ · 2H₂O using the weighing balance and a spatula.

4. Dissolve the Calcium Chloride:

   • Half-fill the 1-liter volumetric flask with distilled water.
   • Add the weighed CaCl₂ · 2H₂O to the flask, using a funnel if necessary to avoid spillage.
   • Swirl the flask gently to dissolve the solid completely. Ensure all the calcium chloride is dissolved before proceeding.

5. Dilute to the Final Volume:

   • Once the CaCl₂ · 2H₂O is completely dissolved, carefully add distilled water to the flask until the solution reaches the 1-liter mark on the volumetric flask. Make sure the bottom of the meniscus aligns with the mark at eye level for accurate measurement.

6. Mix Thoroughly: Invert the flask several times to ensure the solution is homogeneous.

7. Storage: Store the calcium standard solution in a clean, labeled bottle. Include the concentration (0.1M CaCl₂) and the date of preparation on the label.

Important Considerations:

• Use Distilled Water: Always use distilled or deionized water to avoid introducing impurities that can affect the accuracy of your standard solution.
• Reagent Grade Chemicals: Ensure that you use reagent-grade calcium chloride dihydrate (CaCl₂ · 2H₂O) to minimize potential contaminants.
• Accuracy: Accurate weighing and volume measurement are crucial for precise standard solutions.
• Safety: Wear appropriate personal protective equipment (PPE) like gloves and eye protection when handling chemicals.