Chemistry - Metallurgy Question with Solution | TestHub

The Ellingham diagram plots $\Delta G^{\circ }$ vs. T for oxide formation.

Option A is correct: It shows the feasibility of reduction by comparing $\Delta G^{\circ }$ of metal oxide formation with that of the reducing agent's oxide.

Option B is incorrect: The point where $\Delta G^{\circ }=0$ indicates the temperature above which the oxide is unstable and can decompose spontaneously. Below this point, $\Delta G^{\circ }$ is negative, meaning the oxide is stable.

Option C is incorrect: Reduction of metal sulfides is generally more difficult than oxides due to their higher stability, meaning a similar diagram would show less feasibility.

Option D is incorrect: The plot is of $\Delta G^{\circ }$ vs. T, not $\Delta S^{\circ }/T$. $\Delta G^{\circ }=\Delta H^{\circ }-T\Delta S^{\circ }$.