Final answer:
Adding more H₂ to the equilibrium reaction H₂(g) + I₂(g) ⇌ 2HI(g) will shift the equilibrium towards forming more HI, as the system responds to re-establish equilibrium C) More HI.
Step-by-step explanation:
The question asks about the direction in which the equilibrium will shift for the reaction H₂(g) + I₂(g) ⇌ 2HI(g) when additional hydrogen (H₂) is added. According to Le Chatelier's principle, when a change is made to the conditions of a system at equilibrium, the system will adjust to counteract the change and re-establish equilibrium.
If more H₂ is added to the system, this will increase the concentration of a reactant, which shifts the equilibrium to the right, favoring the formation of more product (HI). Therefore, the equilibrium would shift to make more HI, which is option C.