What is the expected behavior of a solute that is more polar in thin-layer chromatography?

In thin-layer chromatography (TLC), the behavior of a solute is heavily influenced by its polarity in relation to both the stationary phase and the mobile phase. The stationary phase in TLC is typically a silica gel or alumina which is polar, while the mobile phase can be a non-polar or slightly polar solvent.

A solute that is more polar interacts strongly with the polar stationary phase. Due to these interactions, it tends to adhere to the stationary phase more than it moves with the solvent front. As a result, a polar solute will not travel far up the plate and will instead remain closer to the baseline where the sample was initially applied. This behavior reflects the principle that polar compounds are more effectively retained by polar stationary phases, leading to shorter migration distances compared to less polar compounds, which can travel further up the plate.

Therefore, the expected behavior of a more polar solute in thin-layer chromatography is indeed that it stays closer to the baseline.