The silver-silver chloride electrode has been investigated in 1-ethyl-3-methylimidazolium chloride/aluminum chloride room-temperature ionic liquids. The electrode is stable only in a narrow range of acidity around the neutral point, but in this range functions as a reversible Ag/AgCl/Cl- system. The electrodes were used to make measurements in buffered and neutral buffered melts to estimate the solubility products land complex formation constants) of several buffering agents; the solubility products are related to the acidity of the buffered neutral melts. For melts buffered with LiCl, NaCl, and KCI, the values of solubility products obtained were in accord with previous measurements where the ratio of solubility products was determined.