The rusting of iron takes place as follows `:`
`2H^(o+)+2e^(-) +(1)/(2)O_(2)rarr H_(2)O(l)," "E^(c-)=+1.23V`
`Fe^(2+)+2e^(-) rarr Fe(s)," "E^(c-)=-0.44V`
Calculae `DeltaG^(c-)` for the net process.

Options

A. `-322kJ" "mol^-1`
B. `-161kJ" "mol^(-1)`
C. `-152kJ" "mol^(-1)`
D. `-76kJ" "mol^(-1)`

Answer

A

Explanation

`Fe(s)toFe^(2+)+2e^(-),DeltaG_(1)^(o)`
`underline("2H^(+)+2e^(-)+1//2O_(2)toH_(2)O(l),DeltaG_(2)^(o)" ")`
`Fe(s)+2H^(+)+1//2O_(2)toFe^(2+)+H_(2)O,DeltaG_(3)^(o)`
Applying, `DeltaG_(1)^(o)+DeltaG_(2)^(o)=DeltaG_(3)^(o)`
`DeltaG_(3)^(o)=(-2Fxx0.44)+(-2Fxx1.23)`
`DeltaG_(3)^(o)=-(2xx96500xx0.44+2xx96500xx1.23)`
`DeltaG_(3)^(o)=-322310J`
`thereforeG_(3)^(o)=-322kJ`