It is demonstrated, using tandem mass spectrometry and ion trap, that preadsorption of a H2O molecule on the gold dimer cation, Au-2(+), enhances adsorption of CO and O-2 molecules, which is otherwise inert toward these molecules. The rate of adsorption of CO on Au-2(H2O)(+) was found to be higher by 2 orders of magnitude relative to bare Au-2(+). The enhancement of the CO adsorption rate is due to the presence of a reaction channel, which cleaves the Au-Au bond, leading to the formation of Au(H2O)(CO)(+). Such an observation can be attributed to weakening of the Au-(A)u bond upon adsorption of a water molecule. Further, it was also observed that preadsorption of H2O leads to dramatic enhancement of O-2 adsorption on the Au-2(+) ion, which can be attributed to the changes in the electron density following water adsorption.