What is the flammability characteristic of hydrogen (H)?

The characteristic of hydrogen regarding flammability is that it is classified as highly flammable. When mixed with air, hydrogen can easily ignite and produce a significant amount of energy. This high flammability is due to the low ignition energy required to ignite hydrogen and its wide range of flammable concentrations in air, which extends from about 4% to 75% by volume.

Hydrogen's potential to ignite and explode when in the right mixture with oxygen makes it critical to handle with care in any setting where it is present. In contrast to other substances that might be classified as not flammable or moderately flammable, hydrogen's properties truly exemplify a high level of flammability, reinforcing the importance of ensuring safety protocols when working with or storing this element.