Give details procedures to prepare stock solution
Here are the detailed procedures to prepare a stock solution:
1. Determine the concentration required: First, you need to know the desired concentration of the stock solution. This is usually stated in terms of molarity (moles per liter) or percentage (%).
2. Calculate the amount of solute needed: Using the desired concentration and volume of the stock solution, you can calculate the amount of solute required. This is done using the formula:
Mass of Solute (g) = Concentration (mol/L) x Volume of Solution (L) x Molar Mass of Solute (g/mol)
Alternatively, if working with a solid solute, the formula can be modified to:
Mass of Solute (g) = Concentration (%) x Volume of Solution (mL) x Density of Solute (g/mL)
3. Select the appropriate solvent: Choose a suitable solvent that can dissolve the solute completely and create a stable solution. Common solvents include water, ethanol, acetone, and various organic solvents.
4. Weigh or measure the solute: Using an analytical balance or a measuring instrument, accurately weigh or measure the calculated amount of solute.
5. Transfer the solute into a suitable container: Choose a container that is chemically inert and can hold the desired volume of solution. Glass beakers or flasks are commonly used. Ensure the container is clean and free from any residues that may contaminate the solution.
6. Add the solvent: Add the calculated volume of the chosen solvent slowly to the solute. Stir or swirl gently to aid dissolution. For solid solutes, heat may be required to facilitate the dissolving process. If necessary, use a hot plate or water bath (with proper safety precautions).
7. Mix thoroughly: Use a glass stirring rod or magnetic stirrer to mix the contents properly until the solute is completely dissolved. This is important to ensure uniformity of the stock solution.
8. Transfer to a volumetric flask: If necessary, transfer the solution to a volumetric flask using a funnel to accurately measure the volume. Rinse the container and the funnel with a small portion of the solvent to ensure complete transfer of the solute.
9. Dilute to the desired volume: Add more solvent to the volumetric flask using a pipette or burette to achieve the final desired volume. Use a meniscus reading at eye level to accurately measure the volume.
10. Mix again and label the solution: Mix the solution thoroughly by inverting the flask several times. Then, label the container with the necessary information, such as the concentration, solvent used, date of preparation, and any additional safety precautions.
11. Store the stock solution: Store the prepared stock solution in a suitable container, away from direct light or heat, at the recommended temperature and conditions. It is advisable to prepare only the amount needed and store any remaining solution for future use.