Adsorption chromatography is based on the principle that different compounds are adsorbed on an adsorbent (stationary phase) to different degrees. In column chromatography a glass column is packed with alumina or silica gel as the stationary phase, the mixture is loaded at the top, and a mobile solvent (eluent) is passed through. Components that are more strongly adsorbed on the stationary phase cling to it more tightly, move down the column slowly, and therefore elute later, while weakly adsorbed components travel faster and elute earlier. This differential retention separates the mixture into bands. The option saying greater adsorption elutes first is the reverse of the truth and is incorrect. The option that all components elute together would mean no separation occurs, contradicting the purpose of chromatography. Dependence on colour alone is wrong because separation arises from adsorption affinity, not pigmentation, though colour can help visualise coloured bands. This adsorption-based retention order is the NCERT basis of column chromatography. Plausibility check: stronger sticking to the stationary phase must slow a component down, so it logically emerges last.