AbstractThe electrophoretic mobilities of adsorbed yeast ribonucleic acid have been measured as functions of pH, ionic strength, and biopolymer concentration and the results so obtained have been critically compared with those for adsorbed DNA. Like DNA, ribonucleic acid has also been found to reverse the positive charge of alumina owing to its adsorption on the solid‐liquid interface. The mobilities of adsorbed RNA have been found to be less than those of adsorbed DNA under identical conditions. The observed mobilities of adsorbed heat‐ and alkali‐denatured RNA are significantly less than those of adsorbed native RNA at a given pH and ionic strength of the medium. The electrophoretic mobilities as observed also show the evidence of RNA adsorption on the negatively charged surface of Dowex‐50 resin, but practically no adsorption of RNA on the negatively charged glass surface has been pr