The radiolysis of hydrocarbons containing dissolved D2S leads to HD, D2, and H2formation, the total hydrogen yields being greater than those in the absence of D2S. A limiting yield of HD is attained at low D2S concentrations (~5 mole%) in all solvents studied. This limiting yield is equal toG(H•) in ethane at 195°K but not inc-C6H12at 298°K whenG(HD) is much greater than accepted values ofG(H•). D2S behaves as both an electron and a positive ion scavenger, most of the D2and probably some of the HD being formed in these processes. The use of D2S to determine H atom and ion yields in irradiated alkanes is not recommended.