Concept:Le Chatelier's principle dictates that increasing pressure on a gaseous system favors the direction that produces fewer moles of gas.
Formula:$$ \text{N}_{2(g)} + 3\text{H}_{2(g)} \rightleftharpoons 2\text{NH}_{3(g)} $$
Solution:- In the Haber process, 4 total moles of reactant gases form only 2 moles of product gas.
- By applying a massive pressure of 200 atm, the system is highly stressed.
- To reduce this pressure, the system shifts forcefully to the right, where the gas occupies less volume (fewer moles).
- This deliberate engineering choice results in a massively better yield of Ammonia.
Why other options are incorrect:Lowering yield makes no industrial sense. High pressure increases the reaction rate, not lowers it. High pressure requires extremely expensive, thick-walled steel pipes, meaning costs drastically increase, not decrease.
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