The Primary Species Yields in the 60 Co g-Ray Radiolysis of Aqueous Solutions of H 2 SO 4 between pH 7 and 0.46

$G({\rm H}_{2}{\rm O}_{2})$ was measured in aqueous solutions containing different low concentrations of ${\rm O}_{2}+{\rm Br}^{-}$ and $G({\rm H}_{2})$ was measured in dilute solutions of KBr at different pH values between 7 and 0.46. Assuming material balance for the primary species from water and using earlier measurements of $G({\rm H}_{2}{\rm O}_{2})$ from solutions of ${\rm H}_{2}+{\rm O}_{2}$, the zero scavenger concentration primary yields $G{}^{0}{}_{(e_{{\rm aq}}{}^{-}+{\rm H})},G{}^{0}{}_{{\rm H}_{2}},G{}^{0}{}_{{\rm OH}}$, and $G{}^{0}{}_{{\rm H}_{2}{\rm O}_{2}}$ from water, were calculated between pH 7 and 1. Precise values for these yields can not be obtained at pH 0.46 because of the complications from the direct absorption of the γ-rays in H2 SO4. The resulting principal molecular product is peroxymonosulfuric acid, for which the yield $G({\rm H}_{2}{\rm SO}_{5})=0.06$ was measured. The yield of peroxydisulfuric acid was negligible. The primary species yield from water were confirmed at pH 1.51-0.46 by measuring G[Ce(III)] and $G({\rm O}_{2})$ in the gas-free Ce(IV) + Ce(III) system, and between pH 2.74 and 0.46 by application of G[Fe(III)] measured at different low concentrations of O2 in 0.1 mM FeSO4 and extrapolated to zero concentration of O2. Further confirmation was obtained at pH 7 from the radiolytic decomposition of the gas-free H2 O2 system, for which reaction earlier workers obtained considerably lower yields than expected from the present study. The disagreement was eliminated by introducing various improvements in the experimental techniques.