Ellingham diagram represents:

Options

A. `DeltaG` with temperature
B. `DeltaH` with temperature
C. `DeltaH` with pressure
D. `(DeltaG-TDeltaS)` with temperature

Answer

### Step-by-Step Solution:

1. **Understanding the Ellingham Diagram**: The Ellingham diagram is a graphical representation that illustrates how the stability of various compounds changes with temperature. It is particularly useful in metallurgy and thermodynamics.

2. **Identifying the Axes**: In the Ellingham diagram, the x-axis typically represents temperature (in degrees Celsius or Kelvin), while the y-axis represents the Gibbs free energy change (ΔG) for the formation of compounds.

3. **Analyzing the Relationship**: The diagram shows that as temperature increases, the Gibbs free energy change for different reactions can either increase or decrease, indicating whether a compound is stable or unstable at that temperature.

4. **Conclusion**: Therefore, the Ellingham diagram represents the relationship between the Gibbs free energy change (ΔG) of various compounds and temperature.

5. **Final Answer**: The correct representation of the Ellingham diagram is the plot of ΔG versus temperature.