Question

If the reduction reaction has a reduction potential of 0.1 V, and the oxidation reaction has a reduction potential of -0.4V, and 2 electrons were transfered, what is the value of delta G expressed in terms of F?

Answer 1

Answer : The value of ΔG expressed in terms of F is, -1 F

Explanation :

First we have to calculate the standard electrode potential of the cell.

$E^o=E^o_{cathode}-E^o_{anode}$

or,

$E^o=E^o_{reduction}-E^o_{oxidation}$

$E^o=(0.1V)-(-0.4V)=+0.5V$

Now we have to calculate the standard cell potential.

Formula used :

$\Delta G^o=-nFE^o$

where,

$\Delta G^o$ = Gibbs free energy = ?

n = number of electrons = 2

F = Faraday constant

$E^o$ = standard e.m.f of cell = +0.5 V

Now put all the given values in this formula, we get the Gibbs free energy.

$\Delta G^o=-(2\times F\times 0.5)$

$\Delta G^o=-1F$

Therefore, the value of ΔG expressed in terms of F is, -1 F