3. The Haber–Bosch process for fixation of nitrogen is one of the more important chemical reactions ever invented. Without the invention of this process, which is used to make ammonia for fertilizer, the world’s population would not be as large as it is today.

N2(g) + 3H2(g)  2NH3(g)

• List three ways in which the yield of ammonia in the reaction above can be improved for a given amount of H2.
• Additionally, explain the principle behind each method.

Increase pressure which shifts the equilibrium to the right.

Increase concns N2 and H2 which drives the reaction to the right.
Decrease the volume which drives the reaction to the right.

I don't think increasing T or adding a catalyst (both which are done in commercial production) count here. Increasing T increases the speed of the reaction as does adding a catalyst but the question doesn't ask about speed; only ways to improve the yield.

Three ways to improve the yield of ammonia in the reaction N2(g) + 3H2(g) → 2NH3(g) are:

1. Increasing the pressure: According to Le Chatelier's principle, increasing the pressure tends to favor the side of the reaction with the fewer moles of gas. In this reaction, the total number of moles decreases from four (N2 + 3H2) to two (2NH3). Therefore, by increasing the pressure, the reaction is driven towards the formation of more ammonia.

2. Lowering the temperature: The forward reaction is exothermic, meaning it releases heat. According to Le Chatelier's principle, if we lower the temperature, the system will try to counteract this change by favoring the side of the reaction that releases heat. In this case, lowering the temperature will increase the yield of ammonia.

3. Removing ammonia as it forms: By continuously removing the ammonia from the reaction mixture, the equilibrium is driven towards the forward reaction to replace the removed product. This can be achieved by either continuously removing the ammonia gas or by absorbing it by using a suitable absorbent, such as a solution of sulfuric acid.

By applying these three methods, the reaction conditions are manipulated to shift the equilibrium towards the production of more ammonia, increasing the yield of ammonia for a given amount of H2.