or reaction , 4Al(s) + 3O2(g) + 6H2O + 4OH- ===== 4[Al(OH)-]; Eo cell = 2.73 V. If ÎGo f(OH-)= -157kj/mol and ÎGof(H2O) = -237.2 kj/mol , determine ÎGo f[Al(OH-)4].
Please explain briefly .
Eocell = 2.73 V
We know that, ΔG = -nfE0
There, n = no of electrons taking part in the reaction i.e. 4 in this case
ΔGtotal = - 1053 kj/ mol
ΔG = ΔG react - ΔG prod
4Al(s) + 3O2(g) + 6H2O + 4OH- =====> 4[Al(OH)-]
0 + 0 + (6x-237.2) + (4x-157) ---- Since Gibbs free energy of Al and O2 is zero, as they are present in their standard state
= -2060 kj = ΔG react
-1053 = -2060 - ΔG of 4[Al(OH)-]
ΔG of 4[Al(OH)-] = -1007 kj/ mol
ΔG = -251.75 kj/mol for [Al(OH)-]