Which graph shows how pressure and temperature affect the yield of ammonia produced by the Haber process? (A)  - HSC - SSCE Chemistry - Question 12 - 2006 - Paper 1

The graph that accurately represents the relationship between pressure, temperature, and the yield of ammonia in the Haber process is graph (A).

In the Haber process, increasing the pressure tends to favor the formation of ammonia, while the effect of temperature is a bit more nuanced. Higher temperatures generally favor the reverse reaction (the decomposition of ammonia back into nitrogen and hydrogen), thus reducing yield.

Therefore, for optimal yield, a balance between high pressure and a moderate temperature (around 400-450°C) is ideal.