Hydrogen at standard temperature and
pressure it is a colorless, odorless, nonmetallic, univalent, highly flammable
diatomic gas. Hydrogen is the lightest and most abundant element in the
universe. It is present in water, all organic compounds and in all living
organisms. Hydrogen is able to react chemically with most other elements. The
element is used in hydrogenation of fat and oil, and also used in ammonia
production, in petrochemical (hydro cracking), as a lifting gas, as an
alternative fuel, and more recently as a power source of fuel cells.