![]() → Three curves cross each other at 1073 K. These three curves are represented in figure 6.6. In Ellingham diagram, there are three curves which illustrate the following reactions : Reduction of Haematite : Ellingham diagram can easily explain the reduction of haematite. It helps to predict reactions of metals with non-metals such as nitrogen and sulphur.Application of Ellingham Diagram Chemistry Notes.It is widely used in the identification of the most suitable reducing agent for the reduction of metal ores.The diagram represents how the stability of compounds is dependent on the temperature.The Ellingham Diagram is a graph of Gibbs energy (ΔG) versus Temperature (T) for the formation of oxide of a metal.For instance, if more than 1 oxide of a metal can be formed, the information for the same through the Ellingham diagram cannot be attained. ![]() The diagram fails to provide complete information regarding the oxides and their formations.The kinetics of the reactions are not taken into consideration in the Ellingham Diagram.The Ellingham Diagram is used to identify the point of equilibrium of the oxidation-reduction process.By referring to the Ellingham curve for Aluminum, it was inferred that it is an efficient reducing agent in the thermite process, aiding in the extraction of Chromium and Manganese through the reduction of their respective oxides.It provides a reference on how to best purify the metals and for the removal of impurities.Ellingham Diagram facilitates a more efficient selection of the best reducing agent for a range of ores.Hence, the entropy is positive resulting in a curve that goes downwards. 2C (s) + O 2 (g) → 2CO (g): In this reaction, a single molecule is leading to the formation of two molecules of gas.Hence, the entropy is null and the slope is zero which is represented by a horizontal line. C (s) + O 2 (g) → CO 2 (g): In this reaction, a single molecule is leading to the formation of another single molecule of gas.Some cases can be observed for which when the entropy is positive, the slope for the substances is downwards. Some metal oxides like HgO, MgO show a drastic change in their slope at a given temperature.For a majority of metals, the slope for the formation of their respective oxide is found to be positive.Any metal that lies above another metal in the Ellingham diagram has the ability to reduce it.Get a complete insight on Ellingham Diagram For temperatures up to this temperature, the free energy for the formation of oxides is negative.This leads to the oxide being unstable which results in its decomposition into its respective metal and oxygen. Beyond this temperature, the free energy for the formation of the oxide is positive.According to the Ellingham diagram on increasing the temperature, after a certain point, ΔG will be zero.When the substance changes its state, an increase in the slope on the positive side is observed.The line for the change of Gibbs energy is a straight line unless the substance does not change its state to liquid or gas.The graphs of metal to metal oxide reactions for a majority of metals shows a positive slope.It is a plot of Δ fGo in kJ/mol of oxygen versus the temperature for the formation of oxides.The video below explains this: Ellingham Diagram Detailed Video Explanation: The Ellingham diagram helps in determining the favourable conditions under which an ore will turn into its metal form. The analysis done through the Ellingham diagram helps in determining the equilibrium temperature between the metal, its oxides and oxygen and through the process of extension helps in predicting the reaction between a metal with sulphur, nitrogen and other non-metals. An Ellingham diagram is referred to as a graphical representation that shows the dependence of a compound stability on the temperature.
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