Water vapor dissociated by an electric discharge and passed into a cold trap yielded products which gave off oxygen at temperatures above −120°C. and at room temperature consisted of hydrogen peroxide and water. With products formed under given conditions, the amount of oxygen evolved with warming was proportional to the total amount of product and independent of the warming procedure. The evolution proceeded to completion at −78°C. Water was found at all trap temperatures between −78°C. and −195°C. Hydrogen peroxide was formed only if the trap temperature was below −120°C., and oxygen was evolved only from products formed below −150°C. The yields of water, hydrogen peroxide, and evolved oxygen all increased with decreasing trap temperature. As the volume of reaction chambers inserted between the discharge tube and the trap was increased, the yield of hydrogen peroxide decreased continuously, while the yield of water at first decreased and then increased to a limiting value. Packing a given reaction chamber with glass wool drastically reduced the yield of hydrogen peroxide, but had little effect on the yield of water. Packing the trap itself had only a slight effect on the yields. The results are compared with those obtained by others with the H–O2 system at low temperatures, and a mechanism is proposed to correlate the two systems.
