Which technique uses a column packed with an adsorbent such as silica gel or alumina to separate components?

• A. Paper Chromatography
• B. Thin-Layer Chromatography
• C. Column Chromatography
• D. Diafiltration

Answer: (C)

Column chromatography separates components by passing a liquid through a column packed with an adsorbent like silica gel or alumina. The different affinities of each component for the stationary phase cause them to travel at different speeds; those that interact more strongly with the adsorbent move slowly, while weaker interactions let others move faster. By collecting fractions as the components elute, you can isolate individual compounds. This setup is distinct from paper or thin-layer chromatography, which use flat plates or paper as the stationary phase, and from diafiltration, which relies on membranes to separate by size rather than adsorption.