Hydrogen gas and oxygen gas can react to form liquid water at 298 K, yet a sealed flask containing only H₂(g) and O₂(g) shows no measurable change after several hours. Which of the following most strongly supports this observation?
a) The reaction mixture is at equilibrium at 298K, so no further net change is possible.
b) Although ΔG∘ for the reaction is negative, the activation energy for forming water is so large that the reaction rate at 298K is effectively zero.
c) The reaction is endergonic at 298K, so the products are higher in free energy than the reactants.
d) A catalyst would be required to move the equilibrium toward liquid water; without it, no reaction occurs.