Ask a Teacher

Search



Explain, what is Ellingham diagram?

The graphical representation of  data for the formation of oxides ,that is, for the reaction ,
                    2xM (s or l )  + O2  _________> 2Mx O (s)
is known as  Ellingham diagrams .
Ellingham diagram can be used for getting thermodynamic data relating to many metallurgical reactions .The diagram help us in predicting the feasibility of the thermal reduction of an ore and also help in making a choice for a suitable reducing agent for the reduction of oxides .

(i) Ellingham diagrams are the plots of free energy of formation of () for the oxides,sulphides and halides as a function of temperature .
(ii) Each plot is a straight line except when any phase change occurs .the phase change ,if any, is indicated by an abrupt change in the slope of the line / curve .
(iii) Due to a decrease in entropy ( is - ve ) during oxide formation , the) becomes less negative .As a result ,the curves /lines have positive slope.

(iv) There is a point on each Ellingham plot below which MxO is stable and above it ,it is unstable .


comments powered by Disqus