A student analyzes two neutral organic molecules, X and Y
CHEMISTRY · Single correct · A Level · Chemistry · Chromatography · Chromatography
Problem
A student analyzes two neutral organic molecules, X and Y, by TLC on polar silica gel using a nonpolar solvent. Spot X has Rf=0.80, whereas spot Y has Rf=0.25. Which statement is most consistent with these data?
(a) Molecule X is more strongly adsorbed onto the silica surface than molecule Y, which allows it to be carried farther and yields the higher Rf value.
(b) Molecule X is more polar than molecule Y because polar compounds interact more strongly with the polar silica gel and thus move farther up the plate.
(c) Molecule X is less polar than molecule Y because it interacts more weakly with the stationary phase and therefore travels farther.
(d) Molecule X travels farther because its molar mass is lower than that of molecule Y, enabling it to migrate more quickly with the solvent front.