Decomposition by Radioactive Substances and Ultra-violet Light

Water suffers decomposition when exposed to the action of radium emanation or radioactive substances yielding hydrogen, oxygen, and hydrogen peroxide in varying amounts according to circumstances. All three types of rays, α, β, and γ, appear to be active in this respect. With the β rays hydrogen is the main gaseous product, owing to the reaction proceeding as follows:

2H₂O = H₂O₂ + H₂.

Ultra-violet light behaves like β rays in this respect. Water-vapour, free from air, is decomposed by a silent electric discharge in a similar manner, hydrogen and hydrogen peroxide being produced.