Chemical Properties Of Hydrogen Cylinders

1. Flammability

Hydrogen is an extremely flammable gas with an ignition point of only 574℃. It can burn in air at concentrations ranging from 4% to 75% by volume. The enthalpy change of hydrogen combustion is −286 kJ/mol. When pure hydrogen is ignited at the tip of a tube with a pointed nozzle, it burns quietly in air, producing a pale blue flame.

 

2. Oxidizing Properties

Hydrogen often exhibits oxidizing properties towards reactive metals because it is a diatomic molecule formed by the covalent bonding of hydrogen atoms. Each hydrogen atom can gain an electron to form a negatively charged hydrogen ion. For example, hydrogen reacts with metallic lithium under heating conditions to form lithium hydride. In this reaction, hydrogen acts as an oxidant, gaining an electron from a lithium atom and being reduced to a negatively charged ion.