‌ECu2+∕Cu∘=0.34V,EZn2+∕Zn∘=−0.76V ‌EAg2+∕Ag∘=0.80V,EMg2+∕Mg∘=−2.37V Most negative ∆G∘ value among the given cells in options is of (1) ‌E∘=0.8+0.76=1.56 ‌∴∆G∘=−2×F×1.56 ‌∆G∘=−3.12FV In case of option (2) and (3), E∘=−ve ∴‌‌∆G∘=+‌ ve value ‌, And ∆G∘ for option (4) will come out to be -0.92 FV , which is less negative than in option (1).