Question

Ellingham diagram is a graphical representation of :

• A. $\Delta G$ vs T
• B. $\Delta H$ vs T
• C. $\Delta G$ vs P
• D. ($\Delta G - T\Delta S$) vs T

Hint:

[Image of Ellingham diagram for various metal oxides] The lower a metal's line sits on the Ellingham diagram, the more stable its oxide is, and the more readily it can reduce the oxides of metals located above it.

Answer 1

The Correct Option is A

Step 1: Ellingham diagrams are used to predict the spontaneity of the reduction of metal oxides.
Step 2: They plot the standard Gibbs free energy of formation ($\Delta G^\circ$) per mole of $O_2$ against absolute temperature ($T$).
Step 3: The relation used is $\Delta G^\circ = \Delta H^\circ - T\Delta S^\circ$, which results in a straight line ($y = mx + c$) where slope is $-\Delta S^\circ$.