Free energies of formation (triangle_(f)G)" of "MgO(s) " and "CO (g) at 1273 K and 2273 K are given below : {:(triangle_(f)GMgO (s) = -941 kJ"/mol at "1273K),(triangle_(f)GMgO (s) = -314 kJ"/mol at "2273K),(triangle_(f)G CO (g) = -439 kJ"/mol at "1273K),(triangle_(f)GCO (g) = -6287 kJ"/mol at "2273K):} On the basis of above data, predict the temperature at which carbon can be used as a reducing agent for MgO (s).

Free energies of formation (triangle_(f)G)" of "MgO(s) " and "CO (g) a

1.	Free energies of formation (triangle_(f)G)" of "MgO(s) " and "CO (g) at 1273 K and 2273 K are given below : {:(triangle_(f)GMgO (s) = -941 kJ"/mol at "1273K),(triangle_(f)GMgO (s) = -314 kJ"/mol at "2273K),(triangle_(f)G CO (g) = -439 kJ"/mol at "1273K),(triangle_(f)GCO (g) = -6287 kJ"/mol at "2273K):} On the basis of above data, predict the temperature at which carbon can be used as a reducing agent for MgO (s).
Answer» SOLUTION :`MGO(s)+C (s) to Mg (s) +CO (G)`. `triangle_(f)G = triangle_(f)G [CO (g)] - triangle_(f)G [MgO(s)]` At 1273 K Substituting the `triangle_(f)G` values at 1273 K, we get `triangle_(f)G = -439- (-941) KJ"/"mol = +502 kJ"/"mol` As `triangle_(f)G` is positive at 1273K, reduction is not possible at 1273K. At 2273 K Substituting the values at 2273 K, we get `triangle_(f)G = -628 - (-314) kJ"/"mol = -314 kJ"/"mol` As `triangle_(f)G` is negative at 2273K, reduction is possible at 2273K.