Explanation

The comparative rates at which solutes move in paper chromatography depend on Rf values. 

Rf values (retention factors) represent the ratio of the distance traveled by a solute to the distance traveled by the solvent front on the paper.

Since different solutes have different polarities and affinities for the mobile and stationary phases, they will travel at different speeds, resulting in unique Rf values.

Therefore, the comparative movement of solutes is directly related to their Rf values.