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Question
Answer the following in brief.
Using the relationship ΔG° of cell reaction and the standard potential associated with it, how will you show that the electrical potential is an intensive property?
Solution
Under standard state conditions, electrical work done in a galvanic cell is given by
ΔG° = - nF `"E"_"cell"^circ`
ΔG° is an extensive property since its value depends on the amount of substance. If the stoichiometric equation of redox reaction is multiplied by 2, that is, the number of substances oxidized and reduced are doubled, ΔG° doubles. The moles of electrons transferred also doubles.
The ratio,
`"E"_"cell"^circ = - (triangle"G"^circ)/"nF"` then becomes,
`"E"_"cell"^circ = - (2triangle"G"^circ)/"2nF" = (triangle"G"^circ)/"nF"`
Thus, `"E"_"cell"^circ` remains the same by multiplying the redox reaction by 2. It means `"E"_"cell"^circ` is independent of the amount of substance and is an intensive property.
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