Chemistry - Electrochemistry Question with Solution | TestHub

For given cell reaction,
${\text{ΔG}}^{\text{o}}\text{=}-{\text{nE}}^{\text{o}}\text{F}$
So,${\text{ΔG}}^{\text{o}}\text{=}-\text{12}\text{×}\text{2}\text{.73}\text{×}\text{96500}\text{J}$
$=-3.1613\times {10}^3\text{kJ}$
Now for given reactions,
${\text{ΔG}}^{\text{o}}\text{=}\text{4}\text{×}{\text{G}}_{\text{f}}^{\text{o}}{\left[\text{Al}{\left(\text{OH}\right)}_{\text{4}}\right]}^{-}-\text{6}\text{×}{\text{G}}_{\text{f}}^{\text{o}}\left[{\text{H}}_{\text{2}}\text{O}\right]-\text{4}\text{×}{\text{G}}_{\text{f}}^{\text{o}}\left[{\text{OH}}^{-}\right]$
(Also note that${\mathrm{G}}_{\mathrm{f}}^{\mathrm{o}}$for elements is zero)
$-3.1613\times 10^3=4{\mathrm{G}}_{\mathrm{f}}^{\mathrm{o}}{\left[\mathrm{A}\mathrm{l}{\left(\mathrm{O}\mathrm{H}\right)}_4\right]}^{-}-6\times \left(-237.2\right)-4\times \left(-157\right)$
So,${\text{G}}_{\text{f}}^{\text{o}}{\left[\text{Al}{\left(\text{OH}\right)}_{\text{4}}\right]}^{-}\text{=}-\text{1303}\text{kJ}$