Eocell for reaction, 4Al(s)+3O2(s)+6H2O+4OH−→4[Al(OH)−4] is 2.73 V. If △Gof for OH− and H2O are - 157 kJ mol−1 and - 237.2 kJ mol−1. If △Gof for [Al(OH)4]− is x kJ. −x is:
Open in App
Solution
For given cell reaction,
ΔGo=−nEoF
∴ΔGo=−12×2.73×96500J
=−3.1613×103kJ
[n=12∴4Alo→4Al3++12e⇌3Oo2+12e→6O2−]
Now for given reactions,
ΔGo=4×Gof[Al(OH)4]−−6×Gof[H2O]−4×Gof[OH−]
(Also note that Gof for elements is zero) −3.1613×103=4×Gof[Al(OH)4]−−6×(−237.2)−4×(−157)