10.4 Haber process and use of NPK fertilisers

• What is the main product of the Haber process?

  Ammonia
• What are the raw materials used in the Haber process?

  Nitrogen and hydrogen
• How is nitrogen obtained for the Haber process?

  From the air
• What sources can hydrogen be obtained from in the Haber process?

  Natural gas or other sources
• What conditions are used in the Haber process?

  High temperature and high pressure
• What is the catalyst used in the Haber process?

  Iron
• At what temperature is the Haber process typically conducted?

  About 450 °C
• What is the pressure used in the Haber process?

  About 200 atmospheres
• What happens to hydrogen and nitrogen in the Haber process?

  They react to form ammonia
• What is the chemical equation for the Haber process?

  N₂ + 3H₂ ⇋ 2NH₃
• What does the term "dynamic equilibrium" mean in the context of the Haber process?

  Forward and backward reactions continue
• Why is increasing pressure beneficial in the Haber process?

  It shifts equilibrium to produce more ammonia
• Why is a low temperature favored for the forward reaction in the Haber process?

  It favors the exothermic forward reaction
• What is the trade-off with using low temperature in the Haber process?

  It slows down the reaction rate
• Why are very high pressures not used in the Haber process?

  They require too much energy
• What are NPK fertilizers used for?

  To improve agricultural productivity
• What do NPK fertilizers contain?

  Compounds of nitrogen, phosphorus, and potassium
• How can NPK fertilizers be produced industrially?

  Using various raw materials in integrated processes
• What are NPK fertilizers formulations made of?

  Various salts with appropriate element percentages
• How can ammonia be used in fertilizer production?

  To manufacture ammonium salts and nitric acid
• How is potassium chloride obtained?

  By mining
• Why can't phosphate rock be used directly as fertilizer?

  It is insoluble in water
• What happens to phosphate rock when treated with nitric acid?

  It produces soluble salts for fertilizers
• What is produced when phosphate rock reacts with nitric acid?

  Phosphoric acid and calcium nitrate
• What is the result of reacting phosphate rock with sulfuric acid?

  Single superphosphate is produced
• What does reacting phosphate rock with phosphoric acid yield?

  Calcium phosphate, known as triple superphosphate
• What are the steps involved in the Haber process?

  1. Obtain nitrogen from the air.
  2. Obtain hydrogen from natural gas or other sources.
  3. Purify gases and pass over iron catalyst.
  4. Maintain high temperature (450 °C) and pressure (200 atmospheres).
  5. Ammonia is formed and removed upon cooling.
  6. Recycle remaining nitrogen and hydrogen.
• What are the reaction conditions and compromises in the Haber process?

  • Dynamic equilibrium is established.
  • Increase pressure to favor ammonia production.
  • Low temperature favors the forward reaction.
  • Actual conditions are moderate to balance rate and yield.
• What are the processes for producing NPK fertilizers from phosphate rock?

  1. React with nitric acid to yield phosphoric acid and calcium nitrate.
  2. React with sulfuric acid to produce single superphosphate.
  3. React with phosphoric acid to yield triple superphosphate.