Thin-layer chromatography (TLC) separates compounds based on:

A) Size only

B) Differential affinity for the stationary phase (silica) vs. the mobile phase (solvent)

C) Charge only

D) Molecular weight only

Explanation

TLC: polar compounds have higher affinity for silica (low Rf). Nonpolar compounds travel further with nonpolar solvent (higher Rf).