Preparation of 0.1 M Sodium Hydroxide from a 9 M Stock Solution

In this article, we will guide you through the process of preparing 500 mL of a 0.1 M solution of sodium hydroxide (NaOH) using a highly concentrated 9 M stock solution. This is a common task in chemical laboratories and understanding the dilution process can be invaluable.

The Dilution Calculation

The formula for calculating the required volume of the stock solution when preparing a solution of a different concentration is:

C1V1 C2V2

Where:

C1 is the concentration of the stock solution (9 M) V1 is the volume of the stock solution needed (the variable we need to find) C2 is the desired final concentration (0.1 M) V2 is the final volume (500 mL or 0.5 L)

Solving the Equation

First, we rearrange the equation to solve for V1:

V1 (C2 × V2) / C1

Substituting the known values:

V1 (0.1 M × 0.5 L) / 9 M

This simplifies to:

V1 0.05 L / 9 M 0.005556 L

Converting liters to milliliters:

V1 ≈ 5.56 mL

Practical Application

To prepare 500 mL of 0.1 M NaOH, you will need to measure out approximately 5.56 mL of the 9 M stock solution. To do this accurately, you may use a pipette or a micropipette. Following that, dilute the measured stock solution with distilled water until the total volume reaches 500 mL. It is recommended to use a 500 mL volumetric flask for this purpose.

Additional Notes

- The method of calculation can be broken down into steps for clarity:

Write down the known values: Vf 0.500 L, Cf 0.1 M, Ci 9.0 M Solve for the unknown volume: Vi CfVf/Ci 0.1 M × 0.500 L / 9.0 M 0.0056 L ≈ 5.6 mL Ensure accuracy: When measuring the stock solution, use precision tools such as pipettes or micropipettes.

Conclusion

Understanding the dilution process and having the ability to calculate the required volumes accurately is crucial in many chemical labs. By following the steps outlined in this guide, you can successfully prepare the desired concentration of sodium hydroxide.