Correct Answer: C. Rate of movement of solute

The relative solubility of solute in both phases determines how fast or slow each component travels through the chromatography system.

Option Analysis

A. Rate of movement of solvent
Solvent (mobile phase) flow rate is controlled by pump pressure or gravity, independent of solute solubility. Solute properties don’t affect solvent movement.

B. Rate of disappearance of solvent
Solvent doesn’t “disappear”—it continuously flows through the system. Evaporation occurs post-elution but isn’t solubility-dependent.

C. Rate of movement of solute (Correct)
Solutes with higher mobile phase solubility move faster (partition into moving phase). Solutes favoring stationary phase solubility move slower (retained longer). This differential rate creates separation.

D. Rate of disappearance of solute
Solutes don’t disappear; they elute completely. “Disappearance” contradicts mass conservation in chromatography.

Relative solubility of solute in both phases determines the rate of movement of solute—the fundamental principle powering all partition chromatography techniques in GATE Life Sciences.

Separation Mechanism

Solutes partition between stationary phase (adsorption/solubility) and mobile phase (flowing solvent). Higher mobile phase solubility = faster elution. Retention factor (Rf) quantifies this relationship.​

Rate Factors Comparison

GATE Applications

Essential for understanding Rf values, TLC/HPLC optimization, and biochemical purification strategies across molecular biology syllabi.