A. Gas

B. Liquid

C. Solid

D. None of the above

Correct Answer: C. Solid

When the stationary phase is solid in column chromatography, no additional support material is needed as the solid itself provides structural integrity when packed directly into the column.

Option Analysis

A. Gas
Gas cannot serve as a stationary phase in packed columns because it lacks physical structure and cannot be retained within the column. Gases function only as mobile phases in gas chromatography (GC), never stationary.

B. Liquid
Liquid stationary phases require a solid support (like silica or diatomaceous earth) to be coated onto because liquids alone flow with the mobile phase and cannot remain fixed in a column. Without support, they provide no retention mechanism.

C. Solid (Correct)
Solid stationary phases (silica, alumina) are particulate materials that pack directly into columns without support. Their inherent rigidity maintains column structure and enables adsorption-based separation. Examples include silica gel in normal-phase HPLC.

D. None of the above
Incorrect, as solid stationary phases specifically eliminate support needs in packed columns, distinguishing them from liquid-coated systems.

In chromatography, no support is needed when stationary phase is solid because solid particles like silica pack directly into columns, providing both separation and structural stability.

Stationary Phase Types

Solid phases (silica, alumina) function independently in adsorption chromatography. Liquid phases must coat solid supports to prevent flow, while gases cannot be stationary.

Support Requirements

GATE Life Sciences Context

Critical for questions on column chromatography techniques in biochemistry. Solid stationary phases dominate normal-phase and flash chromatography applications.