We’re being asked to calculate for ΔG° for the Ecell with the cell notation:

Cr|Cr ^{3+}||Hg _{2} ^{2+}|Hg(l)

**ΔG° can be calculated from the cell potential using the following equation:**

$\overline{){\mathbf{\u2206}}{\mathbf{G}}{\mathbf{=}}{\mathbf{-}}{\mathbf{nFE}}{{\mathbf{\xb0}}}_{{\mathbf{cell}}}}$

ΔG° = Gibbs Free Energy, J

n = # of e^{-} transferred

F = Faraday’s constant = 96485 J/(mol e^{-})

E°_{cell} = standard cell potential, V

**First, let’s determine ****the cell potential and the number of electrons transferred**** from the cell reaction:**

The value of E°cell for Cr|Cr ^{3+}||Hg _{2} ^{2+}|Hg(l) is 1.78 V. Calculate ΔG° for this reaction at 25 .

a. -1220 kJ

b. -1031 kJ

c. -872 kJ

d. -851 kJ

e. -621 kJ