Radiopolarography of barium and radium

The amalgamation reaction of aqueous ions Ra2+ and Ba2+ has been investigated by means of radiopolarography using tracers of 226Ra (α-emitter) and 131Ba (γ-emitter) in aqueous solution. The slope of the logarithmic transformed waves is close to 1/0.03 V-1. The apparent reversibility of the systems has been observed in different conditions of the supporting electrolyte. The variation of the reversible half wave potential with the square root of the ionic strength μ is obtained and discussed. The extrapolation to μ = 0 provides (Esub(1/2))sub(rev) [Ba2+/Ba(Hg)] = - 1.916 V vs S.C.E. and (Esub(1/2))sub(rev) [Ra2+/Ra(Hg)] = - 1.852 V vs S.C.E. (author)