Hydrogen Flame

The hydrogen flame is a simple one to study, for no solids are present either in the pure gas, in pure air, or in any of the products of combustion.

When first ignited, a jet of hydrogen issuing from a glass tube yields a colourless and almost invisible flame; but as the glass becomes warm the flame acquires a yellow tint in consequence of sodium present in the glass. By employing a platinum nozzle the flame is rendered colourless and practically invisible. It consists of two portions, namely, an inner zone initially of pure gas, which rises in temperature and gradually becomes admixed with air as it passes towards the outer zone where combustion is complete.

It would appear that the combustion of hydrogen between 600° and 1000° C. proceeds in such a manner that hydrogen peroxide is formed in considerable quantity, but rapidly decomposes into water and nascent oxygen. Some of the oxygen atoms unite to form ozone, which decomposes less rapidly than the peroxide. For this reason, under suitable conditions, both hydrogen peroxide and ozone may be detected in the products. The temperature of the hydrogen flame has been determined as lying between 2200° and 2300° C. according to the proportion of oxygen.