The Haber process
Central to the production of fertilisers containing nitrogen, is a supply of ammonia (NH3) which is an essential starting point for the production of fertilisers. Diatomic nitrogen has a triple covalent bond holding the atoms together. This requires a large amount of energy to break, so the direct reaction of nitrogen to hydrogen is not usually possible. The Haber Process overcomes these difficulties.
\(Nitrogen+hydrogen\rightleftharpoons ammonia\)
\(N_{2}(g)+3H_{2}(g)\rightleftharpoons 2NH_{3}(l))\)
The double arrow tells us that the reaction is reversible. This is a problem as the ammonia made easily breaks down into the reactants nitrogen and hydrogen. To make this process economic and efficient, the following conditions apply.
| Condition | Reason |
| Temperature | Moderate/Low temperature 鈥 reaction too slow: High temperature 鈥 ammonia decomposes. |
| Pressure | High - This increases the yield of ammonia. |
| Catalyst | Iron (Fe) speeds up the production of ammonia, saving energy costs. |
| Condenser | This cools the reaction down, turning ammonia into a liquid which is easier to extract. |
| Recycled reactants | Unreacted nitrogen and hydrogen are returned to the reaction, saving money. |
| Condition | Temperature |
|---|---|
| Reason | Moderate/Low temperature 鈥 reaction too slow: High temperature 鈥 ammonia decomposes. |
| Condition | Pressure |
|---|---|
| Reason | High - This increases the yield of ammonia. |
| Condition | Catalyst |
|---|---|
| Reason | Iron (Fe) speeds up the production of ammonia, saving energy costs. |
| Condition | Condenser |
|---|---|
| Reason | This cools the reaction down, turning ammonia into a liquid which is easier to extract. |
| Condition | Recycled reactants |
|---|---|
| Reason | Unreacted nitrogen and hydrogen are returned to the reaction, saving money. |
Ammonia is used in the production of fertilisers using the Haber process