The Eleclrochemistry of Gallium

Electromotive force measurements were made on cells of the type Ga (s or i)/ GaX3 § HX/H2 (Pt) where X is chloride or perehlorate at 20 ~ 25 ~ 28 ~ and 35 ~ for various gallic ion concentrations at several constant acidities. The standard elec-trode potential for the gallium-gallic ion electrode in aqueous solution at 25 ~ is found to be-0.560 • 0.005 volt. The standard free energy at 25 ~ was calculated to be-38,800 cal mole-I. The standard entropy and enthalpy for the cell reaction at 25 ~ were estimated to be-39.2 cal mole- ~ deg-I and-50,500 cal mole-~, respectively. The liquid gallium electrode behaved in an irreversible manner, but eleetroplated solid electrodes behaved satisfactorily