Consider the exothermic Haber process equilibrium: N2(g) + 3 H2(g) <=> 2 NH3(g) with delta H = -92 kJ/mol. According to Le Chatelier's principle, which change shifts the equilibrium to the right?

Answer and explanation

Correct answer: C. Increasing the total pressure

  1. Step 1: Count gaseous moles: 1 mole N2 + 3 moles H2 = 4 moles on the reactant side; 2 moles NH3 on the product side.
  2. Step 2: Increasing pressure shifts equilibrium toward the side with fewer gas moles (the right side).
  3. Step 3: Increasing temperature shifts exothermic reactions to the left.
  4. Step 4: Removing H2 shifts equilibrium to the left to replace lost reactant.
Answer
Increasing the total pressure.
Why not the others: 'Increasing the reaction temperature' shifts exothermic reactions to the left (reactants); 'Removing hydrogen gas' drives equilibrium to the left; 'Adding an inert gas at constant volume' does not alter partial pressures or equilibrium position.

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