What is a characteristic of the least polar compound in silica gel chromatography?

In silica gel chromatography, the degree of polarity significantly influences the movement of compounds through the stationary phase, which in this case is silica gel, a polar material. The least polar compound interacts less with the stationary phase compared to other, more polar compounds. As a result, it experiences less retention time and moves through the column more quickly.

When applying this understanding to the elution order in chromatography, the least polar compound will elute first. This is because it does not form strong interactions with the polar silica gel and is able to travel down the column more rapidly as the solvent (mobile phase) carries it along. In contrast, more polar compounds will have stronger interactions with the silica, leading them to elute later as they take more time to be washed off the column.

The other characteristics do not apply as directly to the behavior of the least polar compound in this context. For instance, eluting last would be characteristic of highly polar compounds that adhere well to the silica surface. Remaining fixed on the column and having the highest boiling point do not specifically correlate with polarity and movement through the chromatography column. Therefore, the proper understanding of polarity's role in chromatography supports the conclusion that the least polar compound elutes first.