What characteristic of compounds allows their identification through Rf values?

The identification of compounds through Rf values is rooted in the principle that different compounds have distinct interactions with both the stationary phase (like paper or silica gel) and the mobile phase (the solvent). Consequently, each compound will move differently when a mixture is applied to a chromatography medium and a solvent is allowed to run through it.

When a substance is dissolved in a solvent and applied to a chromatography plate, the extent to which it travels is indicative of its properties, such as polarity, solubility, and adsorption affinity to the stationary phase. This results in each compound having its unique Rf (retention factor) value, calculated as the distance traveled by the compound divided by the distance traveled by the solvent front. The variability in these Rf values across different substances serves as a distinguishing characteristic that allows chemists to identify an unknown compound by comparing its Rf value to a database or known standards.

The incorrect options do not accurately reflect the nature of Rf values; they suggest uniformity in Rf values across compounds and imply lack of influence from solvent type, which contradicts the fundamental principles of chromatography.