Recycling unreacted gases in the Haber process

Steps:

• Identify the Haber process: N₂ + 3H₂ ⇌ 2NH₃, where equilibrium yields incomplete conversion.
• Recognize that ammonia is separated by cooling and compression to liquefy it.
• Note unreacted N₂ and H₂ are separated from the mixture and returned to the reactor.
• Conclude process X recycles both unreacted gases to improve efficiency.

Why D is correct:

• Le Chatelier's principle drives recycling of unreacted N₂ and H₂ to shift equilibrium rightward, maximizing ammonia yield per the reaction stoichiometry.

Why the others are wrong:

• A: Ammonia is the product removed, not recycled; recycling gases shifts equilibrium, but not by returning ammonia.
• B: Cooling liquefies ammonia for removal, but X involves gas recycling, not initial cooling.
• C: Both N₂ and H₂ are recycled in equal proportions to maintain the 1:3 ratio, not hydrogen only.

Final answer: D