What is the purpose of filtration in chemistry?

Filtration is a physical separation process used in chemistry to separate solid particles from liquids or gases. In this context, the correct answer highlights the primary function of filtration, which is effectively used to separate an insoluble solid from a liquid. During the filtration process, a mixture is passed through a porous material (the filter), allowing the liquid to pass through while retaining the solid particles. This is particularly useful in various laboratory and industrial applications, such as purifying solutions or recovering solid substances.

The other options refer to different processes or contexts that don't align with the fundamental role of filtration. For instance, separating soluble and insoluble solids typically involves other methods like evaporation or crystallization, whereas purifying a gas may require distillation or adsorption techniques. Creating a chemical compound does not pertain to separation processes at all, as it involves chemical reactions rather than physical separations. Thus, focusing on filtering as a means to isolate insoluble solids from liquids encapsulates the essence of this procedure in chemistry.