Lead acetate test process
1. Preparation
1. ** Reagent preparation **: Ensure that there is a sufficient amount of lead acetate reagent with the required purity, and it is properly stored in a dry and cool place to prevent it from getting wet or deteriorating. At the same time, prepare various solvents used with it, such as distilled water, etc., to ensure that the solvent is pure and free of impurities.
2. ** Instrument equipment **: Select a balance with suitable accuracy for accurately weighing lead acetate and other related reagents; prepare a clean and undamaged volumetric bottle for accurately preparing solutions; prepare pipettes, droppers, etc., so as to accurately remove different volumes of liquid; and clean test tubes, beakers and other glass instruments for reaction, and ensure that they have been strictly cleaned and dried.
3. ** Environmental Conditions **: The test should be carried out in an environment with relatively stable temperature (generally recommended at 20 ° C - 25 ° C) and moderate humidity (40% - 60% is appropriate) to avoid interference from external environmental factors on the test results.

II. Solution Preparation
1. ** Preparation of Lead Acetate Solution **: According to the required concentration, use a balance to accurately weigh a certain quality of lead acetate solids. For example, to prepare a 0.1mol/L solution of lead acetate, calculate the required solid mass based on the molar mass of lead acetate. Transfer the weighed lead acetate solid to a clean volumetric flask, first add an appropriate amount of distilled water, gently shake to make the solid initially dissolve, then add water to the scale line of the volumetric flask, shake well, and obtain an accurate concentration of lead acetate solution.
2. ** Preparation of other auxiliary solutions **: If the pH value needs to be adjusted during the test, etc., the required acid-base solution and other auxiliary solutions should be accurately prepared according to the corresponding standards.

3. Test operation
1. ** Sample treatment **: If the test object is a solid sample, it needs to be ground and pulverized to a suitable particle size in order to fully react with the lead acetate solution. For liquid samples, to ensure its uniformity, if there are impurities, it needs to be filtered in advance.
2. ** Reaction Operation **: Take an appropriate amount of the treated sample and place it in a clean test tube, and slowly add a certain volume of lead acetate solution with a pipette. According to the nature of the sample and the expected reaction, the test tube can be shaken appropriately to promote the reaction to proceed fully. Close observation of whether there are color changes, precipitation formation and other phenomena during the reaction process, and record the reaction start time and the phenomenon appearance time.
3. ** Comparison Reference **: At the same time set the blank controlled experiment, that is, except for not adding the sample, other operations are exactly the same as the sample test. By comparing the results of the blank control and the sample test, the reaction between the sample and the lead acetate solution can be judged more accurately.

IV. Results Judgment and Record
1. ** Results judgment basis **: According to the established criteria, if there is a specific color change (such as the formation of black precipitation, which may indicate that the sample contains substances that can react with lead acetate to form lead sulfide) or precipitation characteristics (the color, shape, amount of precipitation, etc.), to determine the presence or absence of related substances in the sample and the approximate content range.
2. ** Detailed record **: The various data in the test process, including sample information, lead acetate solution concentration and dosage, reaction phenomenon, reaction time, result judgment, etc., are recorded in detail and accurately for subsequent analysis and summary.

5. Follow-up cleaning
1. ** Instrument cleaning **: After the test, the used glass instruments, etc. should be cleaned in time according to the standard cleaning process. First rinse off the residual solution with tap water, then brush with a suitable detergent, and finally rinse with distilled water, and dry it upside down for later use.
2. ** Reagent treatment **: If the remaining lead acetate solution and other reagents are no longer used in the short term, they should be properly stored or treated harmlessly in accordance with the regulations to prevent their random discharge from causing pollution to the environment.