1. The document discusses column chromatography, which is a technique used to separate mixtures based on differential adsorption of substances onto a stationary phase. 2. Key aspects covered include the principle of column chromatography, types of adsorption (e.g. normal phase, reversed phase, ion exchange), factors that influence separation like nature of adsorbent and mobile phase, and applications like purification and analysis of mixtures. 3. Column chromatography works by flowing a mobile liquid phase over a packed stationary solid phase, allowing different substances in a mixture to migrate through the column at different rates based on their relative affinities for the mobile vs. stationary phases.