The correct option is C ΔG=−nFEcell
For a spontaneous reaction
ΔG<0
The free energy change ΔG (a thermochemical quantity) and the cell potential Ecell (an electrochemical quantity),both measure the driving force of a chemical reaction
Larger the decrease in free energy, greater would be the emf.
Mathematically,
ΔG=Maximum useful work
ΔG=Welectrical
ΔG=Qtotal×Ecell
Here ,
Qtotal=Total charge
Qtotal=−nF
n=no. of moles of electron transferred in a reactionF=Faraday constant
Faraday constant is the charge on 1 mol of electrons
So,
ΔG=−nF×Ecell
Charge on one electron=1.6×10−19 C
Charge on one mol of electrons (F)=1.6×10−19×NA CF=1.6×10−19×6.022×1023=96487 C