Chromatography is a technique of separating compounds from mixtures of compounds. All the substance in the mixture should be soluble in one solvent. So the students took water as solvent for green food color, which is a mixture of dyes. And through chromatography those dyes separatesout as yellow and blue color. Different heights of those colors on chromatogram are because of different speeds of dyes. It depends on there solubility in solvent or adhesiveness with paper. AHISR Gr 7 enjoyed this Chemistry class.
