Silica Gel Chromatography: Silica gel chromatography is also known as thin layer chromatography. This method relies on different molecules having different polarities. A silica plate is spotted with two solutions and placed in a jar with a small layer of developing solvent. The solvent carries the solutions up the plate. The plate is removed when the solvent has moved close to the top of the plate. The solution that moves the farthest is the less polar of the two. This method can compare polarities as well as determine the purity of a product.