Chemistry - Metallurgy Question with Solution | TestHub

Option A is incorrect. For the reaction $M\to MO$, the entropy change $\Delta S$ is negative (gas O₂ consumed), so the slope of the Ellingham diagram curve $\frac{d(\Delta G)}{dT}=-\Delta S$ is positive.

Option B is correct. At very high temperatures (above approximately 1800 °C), the $\Delta G$ for carbon oxidation becomes more negative than that for MgO formation, allowing carbon to reduce MgO.

Option C is incorrect. In a blast furnace, carbon (as CO) reduces iron oxides to iron.

Option D is incorrect. Extraction of metals primarily involves reduction reactions, not oxidation.