Question

The statement that is INCORRECT about Ellingham diagram is :

• A. provides idea about reduction of metal oxide.
• B. provides idea about the reaction rate.
• C. provides idea about free energy change.
• D. provides idea about changes in the phases during the reaction.

Hint:

A crucial distinction in chemistry is between thermodynamics and kinetics. Thermodynamics ($\Delta G, \Delta H, \Delta S$) tells you *if* a reaction can happen, while kinetics (rate laws, activation energy) tells you *how fast* it happens. Ellingham diagrams are purely thermodynamic tools.

Answer 1

The Correct Option is B

The Ellingham diagram is a useful tool in metallurgical thermodynamics, primarily used to predict the conditions under which a metal oxide can be reduced to its metal form. Let's explore the options and understand why the incorrect statement is about the reaction rate.

1. Provides idea about reduction of metal oxide: The Ellingham diagram plots the change in Gibbs free energy for the oxidation/reduction reactions against temperature. This is specifically used to determine the feasibility of reducing metal oxides by evaluating the change in Gibbs free energy for these reactions. Thus, this statement is correct.
2. Provides idea about the reaction rate: The Ellingham diagram does not provide any information about the kinetics of a reaction, i.e., the rate at which a reaction proceeds. It only gives thermodynamic insights (free energy changes) and not kinetic data. Therefore, this statement is incorrect.
3. Provides idea about free energy change: The main purpose of an Ellingham diagram is to show the change in Gibbs free energy for reactions involving metal oxides as a function of temperature. Hence, this statement is correct.
4. Provides idea about changes in the phases during the reaction: The Ellingham diagram can indicate phase changes when there are abrupt changes in the slope of the lines. This often represents changes in the state of the matter (solid, liquid, gas) participating in the reaction. Thus, this statement is correct.

In conclusion, the statement that is incorrect about the Ellingham diagram is that it 'provides idea about the reaction rate'. This is because the diagram is used to determine the thermodynamic feasibility of a reaction rather than its kinetics.