Ammonia is a poisonous, colourless gas with a pungent smell. Mainly manufactured industrially to be used mainly in agriculture.
The Haber Process
The process that produces ammonia from nitrogen and hydrogen, Ammonia produced is mainly used to make fertilisers.
- Raw materials:
- Nitrogen obtained from the air
- Hydrogen from natural gas, methane
- N2 + 3N2 ⇌ NH3(g)
- forward reaction is endothermic
- Nitrogen and hydrogen are mixed in the ratio of 1:3 by volume.
Conditions required
- Pressure – 200 atm
- Temperature – Optimum temperature of about 450 oC., low enough to get a reasonable yield (safe for economic reasons) hence the need of a catalyst
- Catalyst
- finely divided iron catalyst is used
- it increases the rate of reaction
- finely powdered iron has a bigger surface area for catalysis.
Uses of Ammonia
- manufacture of fertilizers eg ammonium-nitrate
- manufacture of urea
- manufacture of nitric acid
Problems with ammonia
it causes water pollution. Results in eutrophication, the increase inorganic content of water when fertilisers leach into soil and washed into rivers and streams. It causes ground water contamination which is harmful to humans