1. A Chromatographic method has been used to investigate the reversible adsorption of hexane, 1-hexene, and 1,5-hexadiene on an alloy of palladium with 6% ruthenium in the temperature interval from 275‡ to 360‡K. 2. The complex character of the isobars for the adsorption of these hydrocarbons on the alloy indicates the presence of several species in the chemisorption of the hydrocarbons in this temperature range. 3. Hydrogen has a pronounced effect on the adsorption of hexane on the alloy; with increasing partial pressure of hydrogen, the adsorption on the α-phase of the alloy-hydrogen system decreases, and the adsorption on the Β-phase increases. 4. The adsorption and catalytic centers of the alloy surface are substantially different. © 1984 Plenum Publishing Corporation.