Digest Scientific Column: Chemistry of Hydrogen (H)

By Mohammad Musa

The name hydrogen was coined by Antoine Lavoisier. Hydrogen was discovered by Henry Cavendish in 1766 by the action of dilute H2O4 on iron. It was named inflammable air.Hydrogen occurs in free as well as in combined state.

Hydrogen has one electron in its outermost shell, it can lose the valence electron to form a univalent cation and they are good reducing agents. These factors favor the placement of hydrogen in group 1 (Alkali metals). However it differs from group 1 in the sense that its ionization energy is much higher than that of group 1 (Alkali metals) element.

Hydrogen also resembles halogens (group 17) At the same time it differs from it. Hydrogen resembles the halogens in the sense that it has a tendency to gain an electron to form hydride ions just as halogens gain an electron to form halide ions, like halogen molecules, hydrogen molecules are diatomic. 

 Hydrogen exists in several forms which are:

1. Hydride ion (H–)
2. Molecular hydrogen (H2)
3. Atomic hydrogen (H)
4. Proton (H+)
5. molecular hydrogen ion (H2+)

Also, it exists in three isotopic forms

_Protium

_Deuterium

_Tritium

 Some properties of hydrogen are:

1. it is the lightest gas
2. it’s colorless
3. it’s odorless
4. it’s not very reactive since the hydrogen-hydrogen bond energy is high
5. it’s sparingly soluble in water.

Economic importance of hydrogen

Hydrogen liquid is used as an alternate source of energy. The technology involves the production, transportation and storage of energy in the form of liquid hydrogen. Large scale production of hydrogen can be done by electrolysis of water or by thermochemical reaction cycle. 

Another thing is storage of hydrogen in liquid form can be done in vacuum insulated cryogenic tanks or in a metal or in all alloy like iron-titanium alloy as interstitial hydride. Hydrogen fuel has many advantages over conventional fuels in that it is non-polluting and it liberates large amounts of energy on combustion.Photo Hydrogen is used to obtain renewable energy from sunlight by using microscopic organisms such as bacteria or algae.