Ammonia – Preparation and Properties

Ammonia

Ammonia molecule is trigonal pyramidal with the nitrogen atom at the apex. It has 3 bond pairs and 1 lone pair. N is sp³ hybridized.

Ammonia is highly soluble in water and is weakly basic.

Preparation of Ammonia:

Ammonia (NH₃) is manufactured on the commercial scale by Haber’s process.

• Pressure ‒ 200 × 10⁵ Pa
• Temperature ‒ 773 K
• Catalyst ‒ Iron oxide with small amounts of K₂O and Al₂O₃. In the laboratory, ammonia is prepared by reacting NH₄Cl with NaOH.

Properties of Ammonia:

Due to the presence of the lone pair of electrons on the nitrogen atoms, NH₃ is a Lewis base. It can form a coordinate covalent bond with the transition metal ion and form complexes, e.g.

Aqueous NH₃ is also used in the precipitation of metal ions, e.g.

Uses of Ammonia:

• It is used as a refrigerant.
• It is used in the manufacture of nitric acid.
• It is used in the production of nitrogenous fertilizers.