Hydrogen

Hydrogen is a colorless gas that is less dense than air and is highly flammable.

The "pop test" is used to identify hydrogen gas in the school laboratory. A test tube mixture of hydrogen and air will pop when ignited producing water as a by-product. The chemical reaction is

Hydrogen + oxygen ==> Water + Energy

2H₂ + O₂ ==> 2H₂O + Energy

The Hindenburg was a German airship that was filled with hydrogen gas. On landing in the USA in 1937 after a transalantic flight the passenger airship caught fire. Thirty six people died.

The airship did not contain a mixture of hydrogen and oxygen which would of caused and immediate explosion. It burnt as the hydrogen in the airship combined with the oxygen from the atmosphere.

Today, airships use helium gas which is non flammable.

Hydrogen exists as a diatomic molecule and has the formula H₂