Chemistry Equilibrium PMC 2021
PMDC Verified Question 70 of 102
Manufacturing of Ammonia by Haber's process is an:
A
Endothermic reaction
B
Irreversible
C
Exothermic reaction
D
Slow
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Exothermic reaction
Concept:

The Haber-Bosch process involves the formation of strong nitrogen-hydrogen bonds, which releases energy.

Formula:

$$ \text{N}_{2(g)} + 3\text{H}_{2(g)} \rightleftharpoons 2\text{NH}_{3(g)} \quad \Delta H = -92.4 \text{ kJ/mol} $$

Solution:

  • The reaction has a negative enthalpy change (\( \Delta H = -92.4 \text{ kJ/mol} \)).


  • A negative enthalpy change definitively classifies the reaction as exothermic, meaning it releases heat to the surroundings.


Why other options are incorrect:

It is not endothermic (it releases heat, doesn't absorb it). It is highly reversible (hence the need for specific high pressure/low temp constraints). With an iron catalyst, the industrial rate is optimized, not inherently slow.

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