O Levels Chemistry (5070)•5070/11/M/J/21
Explanation
Haber Process Conditions
Steps:
- Recall the Haber-Bosch process: N₂ + 3H₂ ⇌ 2NH₃ (exothermic, ΔH negative).
- High pressure shifts equilibrium right (Le Chatelier's principle, fewer moles of gas on product side).
- Temperature compromise: 400°C balances rate (high T) and yield (low T favors exothermic reaction).
- Standard pressure: 200–300 atm for industrial efficiency.
Why A is correct:
- A (200 atm) matches industrial pressure, maximizing yield per Le Chatelier's principle for the 1:4 gas mole ratio.
Why the others are wrong:
- B (1 atm): Too low; equilibrium favors reactants, poor yield.
- C (10 atm): Insufficient pressure; yield still too low for viability.
- D (1000 atm): Impractically high; excessive energy cost, not used industrially.
Final answer: A
Topic: Reversible reactions and equilibrium
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