In relation to Rf values, what does a higher Rf value indicate about polarity?

A higher Rf (retention factor) value in chromatography indicates lower polarity of a substance relative to the mobile phase used in the process. The Rf value is calculated as the distance traveled by the compound divided by the distance traveled by the solvent front. When substances are separated using a chromatographic technique, non-polar compounds will travel further up the stationary phase compared to polar compounds, which tend to interact more strongly with the stationary phase and therefore travel less distance.

In a typical chromatography setup, the stationary phase is often polar (like silica gel), and the mobile phase can vary in polarity (for example, a non-polar solvent). If a compound has a high Rf value, it means that it has a weaker interaction with the polar stationary phase and, thus, is comparatively less polar. This is a fundamental principle in chromatography where substances' affinities for the stationary or mobile phase reflect their polarity.

Therefore, a higher Rf value corresponds to lower polarity, which is why it is labeled as the correct interpretation of Rf values in this context.