PROPERTIES OF NITROGEN

Nitrogen occurs as combined gas in air. It forms 78% by volume of air. It exists as a diatomic molecule N₂.

It occurs naturally in compounds such as proteins, nitrates and ammonium salts.

LABORATORY PREPARATION OF NITROGEN

Apparatus – delivery tubes, furnace, beaker, trough, Bunsen burner, 2 wash bottles

Chemicals – Air, water, sodium hydroxide

Procedure  

Either:

Nitrogen is prepared from the air by removing oxygen and carbon dioxide. Water is used to push air through sodium hydroxide solution (caustic soda solution) which removes carbon dioxide.

 The remaining gas is passed over heated copper turnings to remove Oxygen.

Nitrogen is collected over water as it is insoluble in water.

OR:
Nitrogen can also be prepared by b heating a mixture of ammonium chloride and sodium nitrite.

Nitrogen is formed by decomposition of ammonium nitrite

INDUSTRIAL PREPARATION (LARGE SCALE)

Industrially, Nitrogen is prepared by fractional distillation;Oxygen is obtained at the same time. Air is purified by removing gas from it.
Then carbondioxide is removed and lastly water vapour. The remaining air is removed and compressed. The liquidified air is allowed to evaporate. Because Nitrogen has a lower boiling point, it evaporates first leaving liquid oxygen.

PROPERTIES OF NITROGEN

Physical

1. it is colourless gas without smell
2. it is a reactive gas
3. it does not burn / doesn’t support combustion
4. it is neither acidic nor basic

Chemical properties

1. Nitrogen is inert unlike Oxygen, it reacts under special conditions for example
2. It reacts with some metals at very high temperatures forming nitrides e.g. Calcium and magnesium.