Chromatography and Rf valueवर्णलेखन और Rf मान

NCERT Fig 8.9 · interactive diagram

Parts and their functions

• Stationary phase (स्थिर प्रावस्था) — TLC: a thin layer of silica gel or alumina on glass. Paper chromatography: water held in the cellulose of special paper is the stationary phase.
• Base line (आधार रेखा) — The mixture is spotted on a pencil line about 2 cm from the bottom, kept above the solvent level.
• Mobile phase (गतिशील प्रावस्था) — The solvent rises by capillary action, carrying the components at different speeds; the highest point it reaches is the solvent front.
• Separated spots (पृथक बिंदु) — A component held less strongly by the stationary phase moves further (A); one adsorbed more strongly moves less (B). Colourless spots are seen under UV light or with iodine vapour.
• Retardation factor (मंदन गुणांक) — Rf = distance moved by the substance ÷ distance moved by the solvent front (always < 1). Each compound has a characteristic Rf in a given solvent.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 8.9. Report a mistake