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Reviewed CSCA Chemistry question · Standard

In the Haber process, N2(g) + 3H2(g) ⇌ 2NH3(g) is exothermic. The process uses an iron catalyst and a temperature of about 450°C. Which of the following best explains why a catalyst is used?

  1. It increases the equilibrium yield of ammonia.
  2. It allows the reaction to reach equilibrium faster at the chosen temperature.
  3. It shifts the equilibrium position to the right.
  4. It reduces the activation energy of the reverse reaction only.
Show the answer and explanation

Correct answer

B. It allows the reaction to reach equilibrium faster at the chosen temperature.

Principle or equation

A catalyst provides an alternative reaction pathway with lower activation energy, speeding up both forward and reverse reactions equally. It does not change the equilibrium position or yield.

Why this answer is correct

The catalyst speeds up the attainment of equilibrium, making the process economically feasible at moderate temperatures. It does not affect the equilibrium constant or shift the equilibrium.

Example

Adding a catalyst to a reaction at equilibrium does not change the concentrations of reactants or products.

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