Barium chloride is a common laboratory reagent used for various applications, such as in the preparation of other chemicals, water treatment, and in medical imaging. Here's how to prepare a standard solution of barium chloride: Materials: Barium chloride (BaCl2) dihydrate, about 20 g Distilled water, about 1 liter A glass container with a lid A magnetic stirrer (optional) Steps: Weigh out about 20 g of barium chloride dihydrate and transfer it to a clean, dry glass container with a lid. Add about 500 ml of distilled water to the container and stir to dissolve the barium chloride. If the barium chloride is not dissolving completely, heat the solution gently while stirring until all the solid has dissolved. Once all the solid is dissolved, add more distilled water to the container to bring the total volume up to 1 liter. Mix the solution thoroughly, either by stirring or by using a magnetic stirrer if available. Store the solution in a clean, labelled container with a tight-fitting lid. Note: Barium chloride is toxic, so it is important to handle it with care and follow appropriate safety precautions. Avoid inhaling the powder or solution, and wear appropriate personal protective equipment such as gloves, safety glasses, and a lab coat. Dispose of any unused solution appropriately, in accordance with local regulations.