Preparation of Nitrogen gas
Nitrogen gas can be prepared from air by burning phosphorous. A small crucible is placed on a cork floating in water. The phosphorous is ignited and the crucible covered immediately by a gas jar. The oxygen present in the jar combines with phosphorous to form phosphorous pentoxide which dissolves in water and the level of water rises in the jar. The gas remaining in the jar is nitrogen.
Laboratory preparation of Nitrogen gas
A mixture of ammonium chloride and sodium nitrite when heated, nitrogen gas will be produced which can be collected by downward displacement of water.
The apparatus is fitted as shown in the figure. When the mixture of ammonium chloride and sodium chloride is heated it begins to decompose. Nitrogen bubbles displace water in the gas jar. Thus nitrogen gas can be collected by downward displacement of water.
Manufacture of Nitrogen gas