Which metal can reduce iron oxide at a temperature below according to the Ellingham diagram?
Aluminum (Al)
Copper (Cu)
Silver (Ag)
Nickel (Ni)
The Ellingham diagram is a graphical representation that shows the stability of oxides as a function of temperature. It helps us understand the feasibility of a particular metal reducing the oxide of another metal. The diagram plots the Gibbs free energy change against temperature for different metal oxides.
In the case of iron oxide (FeO), the reduction process can be represented by the following equation:
In this equation, is being reduced to elemental iron by the addition of carbon (C), which acts as a reducing agent.
To determine if a metal like aluminium can reduce iron oxide, we look for the intersection point on the Ellingham diagram where the line representing the reduction of crosses the line representing the oxidation of aluminium.
aluminium oxidation can be represented by the following equation:
The Ellingham diagram indicates the energy change for this reaction at different temperatures.
If we find a temperature on the diagram where the line representing the reduction of FeO crosses the line representing the oxidation of aluminium, it means that aluminium can reduce iron oxide at that temperature.
In this case, the intersection point between the two lines occurs below on the Ellingham diagram. Therefore, it signifies that aluminium (Al) can reduce iron oxide (FeO) at temperatures below .