Hydrogen

Occurrence of Hydrogen

• Free state:

1. It is found entrapped in rocks and minerals.
2. It is found in traces in volcanic eruptions.
3. It is found in stars.

• Combined state:

1. It is a vital constituent of cells and tissues of plants and animals.
2. It is present in large amount in minerals such as coal and petroleum.
3. It is found in water.
4. It is found mixed with natural gas in coal mines.