Chemistry · Solid State

JEE Main 2024 — 29 January, Shift 2 — Question 68

Chromatographic technique/s based on the principle of differential adsorption is/are

A. Column chromatography

B. Thin layer chromatography

C. Paper chromatography

Choose the most appropriate answer from the options given below:

Answer: C

Column Chromatography: In column chromatography, the stationary phase (e.g., alumina or silica gel) is packed in a column. The mixture to be separated is introduced at the top and eluted with a mobile phase. Separation occurs due to the differential adsorption of components by the stationary phase, where more strongly adsorbed components move slower than less strongly adsorbed ones.
Thin Layer Chromatography (TLC): TLC uses a stationary phase (e.g., silica gel or alumina) coated on a flat, inert support (like a glass plate). The sample is spotted on the plate, and a mobile phase moves up the plate by capillary action. Separation is based on the differential adsorption of components to the stationary phase and their differential solubility in the mobile phase.
Paper Chromatography: While also a separation technique, paper chromatography primarily relies on differential partitioning between the stationary phase (water adsorbed on the cellulose fibers of the paper) and the mobile phase. Although adsorption plays a minor role, partitioning is the dominant mechanism, unlike column and thin-layer chromatography where adsorption is the main principle.

Therefore, both Column Chromatography and Thin Layer Chromatography are based on the principle of differential adsorption.

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