The value of `Delta_r G` for formation of `Cr_2 O_3` is `-540 kJmol^-1` and that of `AI_(2)O_(3)` is `-827 kJ mol^(-1)`.Is the reduction of `Cr_2 O_3` possible with Al?

Explanation

Yes
beginarray/l
.Cr_2 O_3+2 Al rarr Al_2 O_3+2 Cr cdot * ldots fii)
Delta_r G^circ=-827-(-540)=-287 kJmol^-1
endarray
Since the vaiue of .Delta_f G^circ. for the reaction no (iii) is negative. Hence the reduction of .Cr_2 O_3. with .A 1. is feasible.