Question

Ellingham diagram is a plot of _ _ _.

• A. $\Delta_f H^\circ$ versus temperature
• B. $\Delta_r G^\circ$ versus time
• C. $\Delta_r G^\circ$ versus temperature
• D. $\Delta_f H^\circ$ versus time

Hint:

Ellingham diagram always uses Gibbs free energy vs temperature, not enthalpy or time

Answer 1

The Correct Option is C

Step 1: Understand Ellingham diagram.
Ellingham diagram is used in metallurgy to study the feasibility of reduction of metal oxidesIt represents thermodynamic stability of compounds

Step 2: Key parameter plotted.
The diagram plots standard Gibbs free energy change ($\Delta_r G^\circ$) of formation of oxides against temperature

Step 3: Purpose of the graph.
It helps determine whether a reducing agent can reduce a metal oxide based on the position of lines in the graphLower $\Delta G^\circ$ indicates more stable oxide

Step 4: Conclusion.
\[ \boxed{\Delta_r G^\circ \text{ versus temperature}} \]