Question

Which of the following statements related to Ellingham diagrams are correct?
(i) It provides a sound basis for the choice of reducing agent in the reduction of oxides.
(ii) Each Ellingham plot is represented by a straight line untill unless there is some change in phase i.e. solid $\to$ liquid, liquid $\to$ gas and gas $\to$ liquid occurs.
(iii) Diagrams similar to Ellingham can be constructed for sulphides and halides which clearly indicates why reduction of $M_{x}S$ is difficult in comparison to $M_{x}O$.
(iv) Ellingham diagrams predicts the tendency of reduction with a reducing agent and kinetics of the reduction process.

• A. (i), (ii) and (iii)
• B. (i) and (iii)
• C. (i), (ii) and (iv)
• D. (ii) and (iv)

Answer 1

Answer: (B)

Ellingham diagram represents plot between $\Delta G^{\circ }$ and $T$ therefore with increase in temperature phase change Gas $\to$ Liquid is not possible. Ellingham diagram does not give any information about kinetics of the reduction reaction.