Making Stock Solution for use in Pharmacology practicals

Transcript

hi n I'm now going to show you first how to make a concentrated stock solution of sodium chloride and second how to make a diluted solution from it continuing exactly 0.85 percent of sodium chloride what do we need is time selim chloride comes as a powder distilled water a measuring cylinder some perfume a funnel and two bottles for a solution and ... Read More

Key Insights

• 💦 Sodium chloride can be made into a concentrated stock solution by measuring the appropriate amount of powder and mixing it with distilled water.
• ⚾ Calculating the required quantity of sodium chloride based on the desired concentration is essential for accurate preparation.
• 🥳 Diluting the stock solution involves adding specific volumes of the stock solution and water in a precise ratio.
• ❓ Mixing the solution thoroughly ensures even distribution of the solute.
• 😷 Using perfume on top of the solution helps mask any unpleasant odor.
• 🍼 Labels should be added to the bottles specifying the concentration of each solution.
• 👻 Dilution allows for the creation of different concentrations from a single stock solution.

Questions & Answers

Q: How do you make a sodium chloride stock solution for pharmacology practicals?

Weigh 8.5 g of sodium chloride, transfer it to a measuring cylinder, and rinse the weighing boat with distilled water to collect the remaining grains. Add distilled water until the bottom of the meniscus reaches the 100 mL line, mix until the sodium chloride is fully dissolved, and transfer the solution to a labeled stock-solution bottle.

Q: How do you prepare 100 mL of a 0.85% sodium chloride working solution?

Measure 90 mL of distilled water into a clean cylinder, then add 10 mL of the prepared stock solution to reach 100 mL. Mix the solution thoroughly and pour it into the final bottle labeled as the working solution.

Q: How is the amount of sodium chloride for the stock solution calculated?

The preparation uses percentage as grams per 100 mL. For the concentrated stock, the demonstrated calculation requires 8.5 g of sodium chloride in a final volume of 100 mL.

Q: What equipment and materials are needed to make the sodium chloride solutions?

The demonstration uses sodium chloride powder, distilled water, a measuring cylinder, a funnel, two solution bottles, perfume, a balance, a spatula, and a weighing boat. One bottle is used for the stock solution and the other for the diluted working solution.

Q: How should sodium chloride be weighed accurately?

Turn on the balance, confirm that it is clean, and place the empty weighing boat on it. Press the tare button to cancel the boat’s weight, then use the spatula to add sodium chloride until the balance reads 8.5 g.

Q: Why is the weighing boat rinsed after transferring the sodium chloride?

The walls of the weighing boat are washed with water to collect all remaining grains of sodium chloride. The rinse is added to the measuring cylinder so the transferred preparation includes the measured powder.

Q: How is a tenfold dilution made from the stock solution?

Use one part stock solution and nine parts water, producing ten total parts. For a final volume of 100 mL, the demonstrated volumes are 10 mL of stock solution and 90 mL of distilled water.

Q: What steps help ensure the final solution is prepared precisely?

Set the liquid level by aligning the meniscus with the required volume line, including the 100 mL mark for the stock. Mix until the sodium chloride is fully dissolved, mix the diluted solution again, and label the stock and working-solution bottles.

Summary & Key Takeaways

• The content provides a step-by-step guide on making a concentrated stock solution of sodium chloride.

• It explains how to calculate the amount of sodium chloride needed for a specific concentration.

• The video also shows how to dilute the stock solution to achieve a different concentration.