The following reaction occurs in the Blast furnace where iron ore is reduced to iron metal $$Fe_2O_{3(s)} + 3CO_{(g)} \rightleftharpoons Fe_{(l)} + 3CO_{2(g)}$$. Using the Le-Chatelier's principle, predict which one of the following will not disturb the equilibrium.

The reaction: $$Fe_2O_{3(s)} + 3CO_{(g)} \rightleftharpoons Fe_{(l)} + 3CO_{2(g)}$$

Le Chatelier's Principle: The equilibrium shifts in response to changes in concentration, pressure, or temperature.

Key point: Pure solids and pure liquids do NOT affect the equilibrium position because their concentrations (activities) are constant. They do not appear in the equilibrium expression.

$$Fe_2O_3$$ is a solid. Adding more $$Fe_2O_3(s)$$ will not disturb the equilibrium because its activity remains 1.

Adding/removing $$CO_2$$ or removing $$CO$$ would shift the equilibrium as they are gaseous species that appear in the equilibrium expression.

The correct answer is Option (3): Addition of $$Fe_2O_3$$.