How does cooling the gases allows ammonia to be separated from unused hydrogen and nitrogen, and state what happens to these unused gases?

Question

Luna Chen · Accepted Answer

Ammonia is a condensable gas..........

In contrast, dihydrogen and dinitrogen are practically incondensable. Now for the response: #1/2N_2(g) + 3/2H_2(g) rightleftharpoons NH_3(g)# The small amount of ammonia that is present at equilibrium may be condensed on a cold finger; cf. #"normal b.p."# #NH_3=-33.3# #""^@C#; #"normal b.p."# #N_2=-195.8# #""^@C#; #"normal b.p."# #H_2=-252.9# #""^@C#. The substantial difference in boiling point is about the only thing this reaction has got going for it. Even though only 5–10% conversions may be achieved with each pass through the reactor, removal of the ammonia product drives the equilibrium to the right. The unreacted, volatile reactant gases may be recycled back through the reactor, allowing the equilibrium to recommence and good turnovers can be achieved.

Avery Adams · Answer

undefined In the Haber process for ammonia synthesis, the reaction between nitrogen and hydrogen gases under high pressure and temperature yields ammonia along with unreacted nitrogen and hydrogen gases. After the reaction, the gas mixture is cooled, which allows ammonia to condense into a liquid because it has a much higher boiling point compared to nitrogen and hydrogen gases. This physical change enables the separation of ammonia from the unreacted nitrogen and hydrogen. The condensed liquid ammonia can then be removed.

The unused hydrogen and nitrogen gases, which do not condense at the cooling temperatures used to liquefy ammonia, remain in the gaseous state. These gases are not wasted; they are often recycled back into the reactor for another cycle of the Haber process to increase the overall efficiency of ammonia production. This recycling process minimizes the waste of hydrogen and nitrogen, conserving resources and improving the economic feasibility of the process.