Chapter 5, Problem 5.24E

The answers in exercise 5.23 should show that changing the partial pressure changes the instantaneous ${\Delta }_{\text{rxn}}G$ even though the ratio of partial pressures stays the same ( that is, $1:1:1$ for standard pressure conditions is equal to $0.5:0.5:0.5$ for the given conditions). This suggests the interesting possibility that at some equal partial pressure $p$ of all components, the reaction reverses; that is, the instantaneous ${\Delta }_{\text{rxn}}G$ becomes negative. Determine $p$ for this equilibrium. (You will have to use the properties of logarithms as mentioned in the chapter to find the answer.) Is your answer of value to those who work with gases at high pressures, or at low pressures? What is your reasoning?