Based on the intersection of the and lines on the Ellingham diagram (which occurs at approximately o — Metallurgy and Isolation of Elements Chemistry Question

💡 Solution & Explanation

In the Ellingham diagram, the line that is lower at a given temperature represents the more stable oxide, and thus the better reducing agent. Below $983 K$, the $CO \rightarrow CO_2$ line is below the $C \rightarrow CO$ line, making $CO$ the primary reducing agent in the upper, cooler zones of the blast furnace.