Compounds of Nitrogen - Properties and Uses of Ammonia



Physical properties of ammonia

1. Ammonia is a colorless gas with pungent odour.
2. Its freezing and boiling points are 198.4K and 239.7K.
3. It is highly soluble in water.


Uses of ammonia

  • In the manufacture of fertilizers such as urea, ammonium phosphate, ammonium nitrate, ammonium sulphate etc.
  • In the manufacture of rayon.
  • In the manufacture of nitric acid by Ostwald's process.
  • Used as a reagent in laboratory.
  • Used as a refrigeration fliuid.


Structure of ammonia

The ammonia molecule has a trigonal bipyramidal shape as predicted by VSEPR theory with an experimentally determined bond angle of . The central nitrogen atom has five outer electrons with an additional electron from each hydrogen atom. This gives a total of eight electrons, or four electron pairs that are arranged tetrahedrally. Three of these electron pairs are used as bond pairs, which leaves one lone pair of electrons. The lone pair of electrons repel more strongly than bond pairs, therefore, the bond angle is not 109.5, as expected for a regular tetrahedral arrangement, but .The nitrogen atom in the molecule has a lone electron pair, which makes ammonia a base, a proton acceptor.


Chemical properties of ammonia

Thermal Stability: Ammonia is highly stable.
Ammonia is combustible in air.
Basic Character: 
Ammonia molecule has a strong tendency to donate its lone pair of electrons of nitrogen to other molecules.