Atomic and Molecular Hydrogen Yields from Irradiated Acids

Abstract

The paramagnetic-resonance method has been used to measure the yields of atomic hydrogen from many concentrations of aqueous sulfuric, phosphoric, and perchloric acids at 77°K after irradiation with gamma rays. The yields of molecular hydrogen (and oxygen) have also been measured after similarly irradiated acids were warmed and the gases collected. The correspondence between atom and molecule yields is discussed. In sulfuric and phosphoric acids the atom and molecule yields depend upon whether the acid is a glassy or crystalline solid at the time of irradiation. Prolonged irradiation of 0.129-mole-fraction sulfuric acid (glassy) gives a saturation concentration of 3.4×1018 hydrogen atoms per gram. The corresponding number for 0.125-mole-fraction perchloric acid is 2.9×1019. The scavenging effects of nitric acid and hydrogen peroxide on the atomic and molecular hydrogen yields for 0.129-mole-fraction sulfuric acid have been measured and are discussed. The corresponding effect of nitric acid on the atom yield from perchloric acid is presented.