Ammonia


Ammonia is present in small quantities in air and soil where it is formed by the decay of nitrogenous organic matter

On a small scale ammonia is obtained from ammonium salts which decompose when treated with caustic soda or calcium hydroxide

On a large scale, ammonia is manufactured by Haber’s process.

Properties of Ammonia 

  • It is a colourless gas with a pungent odour
  • Its freezing and boiling points are 198.4 and 239.7 K respectively
  • The ammonia molecule is trigonal pyramidal with the nitrogen atom at the apex. It has three bond pairs and one lone pair of electrons

  • Ammonia gas is highly soluble in water. Its aqueous solution is weakly basic due to the formation of OH– ions
  • It forms ammonium salts with acids, e.g., NH4Cl
  • As a weak base, it precipitates the hydroxides (hydrated oxides in case of some metals) of many metals from their salt solution
  • The presence of a lone pair of electrons on the nitrogen atom of the ammonia molecule makes it a Lewis base. It donates the electron pair and forms linkage with metal ions and the formation of such complex compounds finds applications in detection of metal ions such as Cu2+, Ag+




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