In the Haber process for ammonia synthesis, N2(g) + 3H2(g) ⇌ 2NH3(g), the reaction is exothermic. Which condition is used industrially to achieve a reasonable yield while maintaining an adequate rate?
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Correct answer
D. High pressure and moderate temperature with a catalyst
Principle or equation
The Haber process uses high pressure (favoring the side with fewer gas moles) and a moderate temperature (compromise between rate and equilibrium yield) with an iron catalyst. Exothermic reaction favors lower temperature for yield, but too low a temperature slows the rate.
Why this answer is correct
High pressure shifts equilibrium to products (4 moles gas to 2 moles). Moderate temperature (around 450°C) gives a reasonable yield and rate; a catalyst speeds the reaction without affecting equilibrium. Low temperature would increase equilibrium yield but is too slow; high temperature increases rate but lowers yield.
Example
Industrial conditions: 200 atm, 450°C, iron catalyst, with ammonia removed continuously.
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