Which method is commonly used for purifying solids?

Filtration is a widely used method for purifying solids because it effectively separates solid particles from liquids or gases based on their physical size or state. In this process, a mixture containing solid impurities is passed through a porous medium, such as filter paper or a membrane, which allows the liquid to flow through while retaining the solid particles. This technique is particularly helpful when the desired product is a solid and needs to be isolated from a mixture in which it is suspended.

The effectiveness of filtration in removing contaminants makes it ideal for obtaining pure solids from heterogeneous mixtures. In laboratory settings, this method can be employed for various applications, including the purification of precipitates formed during reactions or isolating compounds from reaction mixtures.

Other methods listed, like centrifugation, evaporation, and chromatography, serve different purposes in laboratory processes. Centrifugation separates components based on density differences, primarily used for suspensions, while evaporation is useful for removing solvents from solutions but is not specifically for solid purification. Chromatography involves separating compounds based on their movement through a stationary phase and is more suitable for purifying individual components rather than directly isolating solids from a mixture. Therefore, filtration remains the best choice for solid purification in many organic chemistry applications.