JEE Main · 2023 · 10 Apr 2023 · Shift 1 · Practical and Analytical Chemistry

In column chromatography the component held more strongly by the stationary phase moves down the column more slowly and comes off later, while the weakly held component travels faster and is washed out first. A strongly adsorbed substance also covers a shorter distance relative to the solvent front, which means a smaller retardation factor. Since A is eluted first, A is the weakly adsorbed component with the higher retardation factor, so the component B that comes out later must be the more strongly adsorbed one with a low retardation factor.