A dropping funnel is a type of laboratory apparatus used for adding liquids to a reaction vessel slowly and precisely. It consists of a conical or cylindrical vessel with a stopcock at the bottom that can be opened and closed to control the flow of liquid. Dropping funnels are commonly used in chemistry and biology labs for various applications, such as adding reagents or reactants to a reaction mixture, or for slowly titrating a solution. They are often preferred over other types of dispensing tools for applications where precision and control are important. Dropping funnels are available in a variety of sizes, materials, and shapes to suit different experimental needs. They may be made of glass or plastic, and can be equipped with various types of stopcocks, including PTFE or glass. Overall, dropping funnels are an essential tool for any laboratory or educational setting where precise liquid addition is required. They provide a simple and effective way to control the flow of liquid and to add reagents or other solutions to a reaction mixture with accuracy and reproducibility.