In the Ellingham diagram ( vs ), the plot for the reaction exhibits a unique characteristic compared — Metallurgy and Isolation of Elements Chemistry Question

💡 Solution & Explanation

For $2C_{(s)} + O_{2(g)} \rightarrow 2CO_{(g)}$, 1 mole of $O_2$ gas reacts to form 2 moles of $CO$ gas. Since $\Delta n_g > 0$, the entropy change $\Delta S$ is positive. Using $\Delta G = \Delta H - T\Delta S$, a positive $\Delta S$ makes the slope ($-\Delta S$) negative, causing the line to plunge downwards as $T$ increases.