• Ammonia and nitrogen compounds have a wide range of industrial purposes

Ammonia

• Ammonia is used in the manufacturing of fertilisers which are used to grow crops
  • Plants are unable to directly use the nitrogen that is present in the air
  • Instead, they get their nitrogen from nitrogen compounds dissolved in water which they can absorb from the soil through their roots
  • Without the use of fertilisers, crops will not be able to grow resulting in lack of food to feed the population
  • Some ammonia is injected directly into the soil to act as a fertiliser
• Ammonium hydroxide, also known as household ammonia is used as the main ingredient in many household cleaning products
• Ammonia is also used as a refrigerant gas as it absorbs heat from the surroundings

Nitric acid

• Another purpose of ammonia is in the synthesis of nitric acid
• Nitric acid is used to form dyes but is also used in fertilizers
• Other uses of this nitrogen compound include making explosives (such as TNT)

• The uncontrolled use of nitrate fertilisers can have significant environmental problems
  • Ammonium salts are soluble in water and get washed in to the ground water, rivers and streams causing them to get contaminated with ammonium and nitrate ions
  • This results in eutrophication of streams and rivers
  • When ammonium salts in fertilisers get into the water, there is an increase in plant nutrients
  • Algae that live in the water will feed on these nutrients causing excessive growth of the algae
  • As a result, light cannot reach the lower plants in the water, preventing them from photosynthesising, causing them to die
  • Bacteria feed on the dead plants which decompose by aerobic respiration
  • All the oxygen is used up by the decaying plants, which means that organisms can no longer respire
• Nitrates are also potentially carcinogenic
  • The presence of nitrates in drinking water is dangerous to human health
  • The removal of nitrates from water is too expensive