Study of Compounds- Ammonia – Notes

Group 15: Nitrogen – Ammonia

Ammonia chloride, when heated with lime or caustic soda, evolves ammonia gas.

2NH₄Cl           +     Ca(OH)₂   +    ®D     2NH₃      +  2H₂0  +         CaCl₂

Ammonia chloride   Slaked Lime      Ammonia     water     calcium chloride

In accordance with Le Chatelier’s principle, high pressure, high pressure and low temperature favours the better yield of ammonia.

A high pressure of 200-300 atmospheres, an optimum temperature about 700k and the catalyst iron oxide along with promoter alumina are used to obtain better yields of ammonia.

N₂        +          3H₂                      2NH₃       DH= – 92.2 kJ mol^-1

Nitrogen        Hydrogen                      Ammonia

On account of the presence of one lone pair in ammonia, the geometry of the molecule is trigonal pyramidal.