Answer
C. The equilibrium position would shift to produce more O₂
Step-by-step explanation
If the concentration of a substance is changed, the equilibrium will shift to minimize the effect of that change. If the concentration of a reactant has increased the equilibrium will shift in the direction of the reaction that uses the reactants, so that the reactant concentration decreases.
Therefore, considering the reaction above at equilibrium, what would happen if more Na₂O2 were added is:
C. The equilibrium position would shift to produce more O₂