Nitrogen

The gases present in the atmosphere are nitrogen (about 78%), oxygen (21%) and carbon dioxide (0.03%) by volume.

To isolate nitrogen from atmospheric air, the air is passed through a filter chamber to remove particulate matter such as dust. The filtered air is then passed through sodium hydroxide solution to remove carbon dioxide.

Preparation of nitrogen from ammonium nitrate

Ammonium nitrate solution decomposes on warming to produce nitrogen. Normally this unstable compound is not stored in laboratory but can be prepared when needed.

The double decomposition reaction between the salt yields ammonium nitrate.

i) Preparation of nitrogen by the action of heat on ammonium nitrite

The reaction between sodium nitrite and ammonium chloride gives sodium chloride and ammonium nitrite.

A solution of ammonium nitrite readily decomposes, on slight warming, to give nitrogen gas.

As the solution becomes warm, rapid effervescence occurs as more nitrogen is given off.

The nitrogen evolved may be collected over water because the gas is only slightly soluble in water, at ordinary temperature, and slightly denser than air.

1. Nitrogen is a colourless and odourless gas.
2. It is slightly lighter than air.
3. It is slightly soluble in water.

1. It reacts with red hot metals, like magnesium and calcium to form nitrites.

2. Nitrogen does not burn, nor does it support combustion. When heated, the gas combines with oxygen to form nitrogen monoxide gas:

3. At ordinary pressure and moderately high temperatures, nitrogen reacts with hydrogen in the Haber Process to produce ammonia:

1. It is used in manufacture of nitrogeneous fertilizers in the form of ammonium and nitrate compounds.
2. It is used in the manufacture of ammonia.
3. Liquid nitrogen is used in the refrigeration of biological and industrial materials like semen for artificial insemination.
4. It is used in the manufacture of nitric acid in Haber process.
5. It provides an inert environment for processing and storing reactive substances.