Question

An Ellingham diagram provides information about ______.

Options

• the conditions of pH and potential under which a species is thermodynamically stable. 

• the temperature dependence of the standard Gibbs energies of formation of some metal oxides.

• the pressure dependence of the standard electrode potentials of reduction reactions involved in the extraction of metals.

• the kinetics of the reduction process.

Answer 1

An Ellingham diagram provides information about the temperature dependence of the standard Gibbs energies of formation of some metal oxides.

Explanation:

Ellingham diagram is the graph of ΔG° vs T of any metal/element oxide. Since

ΔG° = ΔH° - TΔS°

For most metal oxide formation:

\[\ce{metal (s) + oxygen (g) -> metal oxide (s)}\]

ΔH° = - ve; ΔS° = - ve

So, graph will be a straight line with -ve intercept and +ve slope.