Standardization involves preparing a solution with a precisely known concentration. Here's how to prepare a standard solution, based on the provided reference, using Sodium hydroxide (NaOH) as an example:
Preparing a Sodium Hydroxide Standard Solution
The reference provides a method to prepare a standard solution of NaOH. The process is outlined below:
- Initial Water Volume: Begin by adding about 100 ml of distilled water into a clean and dried 1000 ml volumetric flask.
- Adding NaOH: Carefully add approximately 4.2 grams of Sodium hydroxide (NaOH) to the flask. Stir continuously to ensure it dissolves properly.
- Dilution: Add an additional 700 ml of distilled water to the flask and thoroughly mix the solution.
- Cooling: Allow the solution to cool to room temperature before proceeding further.
What Happens After Preparation?
While the reference focuses on the preparation stages, it's essential to note that standardization typically means determining the exact concentration of a solution. In the case of NaOH which readily absorbs carbon dioxide from air and is difficult to be prepared as exact solution by weight, this typically involves:
- Titration: Use the prepared solution to titrate a known mass of a primary standard, such as Potassium hydrogen phthalate (KHP).
- Calculation: Use the titration results to calculate the precise concentration of the NaOH solution.
Key Considerations
- Purity of Reactants: The accuracy of the prepared standard depends on using reactants with known purity, such as Sodium Hydroxide and Potassium Hydrogen Phthalate.
- Temperature Control: Volume measurements of liquid are affected by temperature changes, therefore, solution should be prepared and standardized at a constant temperature, usually room temperature.
- Storage: Storing of solutions like NaOH require air tight bottles as they are sensitive to CO2 in the air.
Summary Table for Preparation
| Step | Action | Details |
|---|---|---|
| 1 | Initial Water Addition | Add approximately 100 ml of distilled water to 1000 ml volumetric flask. |
| 2 | Addition of Sodium hydroxide | Add about 4.2 grams of NaOH to the flask with continuous stirring. |
| 3 | Dilution | Add about 700 ml of distilled water, mix well. |
| 4 | Cooling | Allow solution to cool to room temperature. |
| 5 | Standardize the solution | Use a titration method against a primary standard to determine the exact concentration. |
