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Question why is the catalysed reaction faster than the gas phase reaction? Is the overall process exothermic or endothermic? Does the catalyst affect the equilibrium position?
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 Carl Bosch Joint winner of Nobel Prize for Chemistry, 1931 for his work on high- pressure systems |
Answer
Gas phase reaction has very much higher activation energy.
Exothermic
No. A catalyst affects the rate of reaction in both directions, so the equilibrium constant is unchanged.
| The red arrows in the diagram show the activation energies of each of the steps. The exact values vary depending on the surface coverage. |
| Success in manufacturing ammonia depended on finding a catalyst, but equally vital was the ability to put a high-pressure process safely into practice, and much of this success was due to Carl Bosch. Pressures used were around 250-350 atm but since 1960 there has been a steady fall in the synthesis pressure used. |
