Preparing a standard solution | Chemistry

Summary

This video explains how to prepare a standard solution for titration. The process involves accurately weighing the solute using a precise balance, transferring it to a beaker, and dissolving it completely in distilled water. The solution is then transferred to a volumetric flask, ensuring all of it is included by rinsing the beaker and funnel. The flask is filled to the calibration mark with distilled water, ensuring precise measurement by viewing at eye level. The final step is mixing the solution thoroughly by inverting the flask, ensuring homogeneity before use.

Takeaways

• 📏 Calculate the mass of solute accurately using a balance with one to three decimal places.
• ⚖️ Weigh the solute using a top pan balance and transfer it into a glass beaker.
• 🚿 Rinse the weighing boat with distilled water to ensure all solute is transferred.
• 💧 Dissolve the solute completely in distilled water, using a glass stirring rod if needed.
• 🔍 Transfer the dissolved solution into a volumetric flask using a glass funnel, avoiding spills.
• 🧼 Rinse the beaker and glass funnel thoroughly with distilled water to ensure no solution is left behind.
• 🔄 After rinsing, place a stopper in the flask and gently shake to mix the solution.
• 📐 Add distilled water to the volumetric flask until the bottom of the meniscus touches the calibration line, using a pipette if needed.
• 🔒 Store the prepared solution with the stopper firmly in place.
• 🧪 Before use, ensure the solution is homogeneous by gently inverting and shaking the flask.

Q & A

What equipment is used to weigh the solute accurately?

A top pan balance with an accuracy of one to three decimal places is used to weigh the solute.

Why is it important to rinse the weighing boat with distilled water?

Rinsing the weighing boat ensures that all of the solute is transferred into the glass beaker, preventing any loss of material.

How can you ensure that all of the solute is dissolved in the distilled water?

You can ensure that all the solute is dissolved by adding more water if needed, swirling the solution, and using a glass stirring rod if necessary.

What is the purpose of using a volumetric flask in this procedure?

A volumetric flask is used to ensure that the solution is made up to a precise volume, which is necessary for creating a standard solution for accurate measurements.

Why is it important to rinse the beaker and the glass funnel multiple times?

Rinsing the beaker and glass funnel ensures that none of the original solution is left behind, which could alter the concentration of the final solution.

What should you do if any solution is spilled during the transfer process?

If any solution is spilled during the transfer, you need to start the entire process again to ensure accurate results.

Why is it important to view the volumetric flask at eye level when filling it up to the mark?

Viewing at eye level ensures that you can accurately judge the position of the meniscus and fill the flask to the exact line, avoiding overfilling.

What is the meniscus, and how does it relate to the procedure?

The meniscus is the curve seen at the surface of a liquid in response to its container. In this procedure, you should ensure that the bottom of the meniscus is touching the line on the volumetric flask for accurate volume measurement.

Why is it necessary to gently shake the flask after placing the stopper?

Gently shaking the flask ensures that the solution is homogeneous, meaning all the solute is evenly distributed throughout the solvent.

What is a standard solution, and when is it ready for use?

A standard solution is a solution of known concentration that is used in titrations. It is ready for use once the solute is completely dissolved, the solution has been made up to the correct volume, and it has been mixed thoroughly.