How to prepare phenol red solution from powder: detailed steps and precautions

Phenol red solution is an indicator commonly used in chemical experiments, especially in acid-base titration, pH testing and other experiments have a wide range of applications. How to prepare phenol red solution from phenol red powder? This article will introduce the steps of preparing phenol red solution for you in detail, and discuss the key points that need attention in the preparation process.

1. Preparation: Required materials and tools

To successfully prepare a solution of phenol red from powder, you first need to prepare the relevant materials and tools:

• Phenol Red Powder: Make sure to use a higher purity phenol red powder to ensure solution accuracy and stability.
• Solvent: usually use distilled or deionized water, avoid the use of impurities in the water source.
• Weighing Tool: An accurate electronic balance is required to weigh the phenol red powder.
• Container: Choose a suitable glass bottle or beaker to ensure that it can hold the required amount of solution.
• Stirring tool: Use a glass rod or magnetic stirrer to stir the solution to ensure that the phenol red powder is completely dissolved.

2. Determine the phenol red solution concentration

The concentration of phenol red solution depends on the experimental requirements. In general, we will allocate different concentrations of phenol red solution according to specific needs. A common concentration is 1%(w/v) solution, which means 1g of phenol red powder per 100 ml of solution.

For example, if 100 ml of 1% phenol red solution is to be prepared, 1g of phenol red powder is required. This concentration is often used as an acid-base indicator in the laboratory and is sufficient to cause a significant color change in the solution.

3. Phenol red solution preparation steps

1) Weighing phenol red powder

The required amount of phenol red powder was weighed on an electronic balance. Remember to weigh accurately and take care to avoid powder waste or errors. If more solution is required, make sure that the correct mass to volume ratio of the powder is measured.

2) Dissolved powder

Add the weighed phenol red powder into a beaker or container, and add an appropriate amount of distilled water. It is then stirred using a glass rod or magnetic stirrer until the powder is completely dissolved. It should be noted that phenol red dissolves slowly, so stir patiently.

3) Adjust the volume

When the powder is completely dissolved, add more solvent to the vessel, depending on the volume of solution required. At this time, a measuring cylinder or a measuring flask can be used for accurate volume measurement to ensure the accuracy of the solution volume.

4) Check the solution

After the preparation, check whether the color of the solution is uniform. If the color is light or uneven, you can stir it a few times to ensure that the solution is completely mixed.

4. Precautions and Frequently Asked Questions

Incomplete dissolution

In the preparation of phenol red solutions, the powder may sometimes be incompletely dissolved due to solubility issues. At this time, you can try to increase the stirring time, or use heating methods (but not too high temperature) to accelerate the dissolution process. If it still does not dissolve completely, it may be necessary to adjust the pH of the solvent or replace the solvent.

PHENOL RED SOLUTION STORAGE

The phenol red solution should be stored in a closed glass bottle and placed in a cool and dry place away from direct sunlight. Because phenol red is susceptible to light and heat, its color may change after long-term storage, which may affect the experimental results.

5. Summary

How to prepare phenol red solution from powder is actually a relatively simple process, but requires accurate operation and careful attention. In the preparation process, ensuring the quality of phenol red powder, the purity of the solvent and the adequacy of stirring are all key steps to ensure the quality of the solution. If you follow the above steps, you can get a high-quality phenol red solution, which helps you to accurately indicate the acid and base in the experiment.

Through the introduction of this article, I hope you can master how to prepare phenol red solution from powder, and avoid common problems in actual operation, and obtain satisfactory experimental results.