Infrared spectroscopy shows that CaH2 in liquid 1-ethyl-3-methyl-1H-imidazolium chloroaluminates reduces the cation in Lewis basic systems, does not affect the neutral salt, and forms AlCl3H- and eventually allanes in Lewis acidic systems. The AlCl3H-species can be determined by UV-vis spectroscopy through its reaction with 2,3-dichloro-1,4-naphthoquinone to form an alkoxide. While AlCl3H-reacts with protic species to give H-2, its electrochemical oxidation proceeds through H(ads), some of which is oxidized to HI, which can be electrochemically reduced.