Nitrogen

Nitrogen, N2, is a colourless odourless gaseous non-metallic main group element which belong to Group Vb of the periodic table.

Atomic Number : 7
Atomic Mass : 14.007

Discovery

Nitrogen was discovered by D Rutherford in 1772 AD, when he reported in a thesis that it did not support life. His experimental isolation of nitrogen was confirmed by Cavendish in 1785 AD.

Lavoisier called the gas "Azote".

Occurrence

Nitrogen is the most abundant gas in the atmosphere, which is composed of approximately 78% nitrogen gas by volume, or 75.5% by weight.

Extraction

Nitrogen may be prepared from air by passing the air through a solution of caustic soda to remove carbon dioxide.

	2 NaOH    +   CO2   ==>   Na2CO3    +    H2O

Then the gas stream is passed over heated copper turnings which removes the oxygen.

	Cu    +   O2    ==>     2 CuO

However, when nitrogen is prepared by this method, the gas is somewhat impure due to the presence of traces of the inert Nobel Gas, which are also present in the atmosphere.

Nitrogen may also be prepared by the decomposition of compounds containing nitrogen. For example, nitrogen gas is liberated on heating a dilute solution of ammonium nitrite.

	NH4NO2    	==>     N2     +    2 H2O

Preparation

Manufacture

Properties

Although nitrogen is relatively inert chemically, it does react with some metals at high temperature (i.e. dull red heat) to form nitrides.

	3 Mg    +    N2    ==>    Mg3N2

Reactions

Uses

Nitrogen is used for the manufacture of ammonia in the Haber Process. Nitrogen is also used as the filler gas in electric lamps and in high temperature thermometers.

Nitrogen is used to provide an inert atmosphere in metallurgy to prevent oxidation in certain industrial processes.

Detection and Analysis

Nitrogen is a colourless, odourless, nonflammable gas neutral gas, which does not support combustion. Thus, the confirmation of the detection of nitrogen gas is based on a negative inference based on its reactive inertness.

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