Take Delta G deg = -529 + 0.131 T kJ for 2Fe + O2 -> 2FeO and Delta G deg = -221 - 0.179 T kJ for 2C + O2 -> 2CO. Reduction of FeO by carbon, FeO + C -> Fe + CO, becomes spontaneous above approximately

JEE Main levelSingle correct optionDifficulty 2 of 3mt208

Take $Δ G^{\circ} = - 529 + 0.131 T$ kJ for $2 Fe + O X_{2} 2 FeO$ and $Δ G^{\circ} = - 221 - 0.179 T$ kJ for $2 C + O X_{2} 2 CO$ . Reduction of FeO by carbon, $FeO + C Fe + CO$ , becomes spontaneous above approximately

For

FeO + C Fe + CO

Δ G^{\circ} = \frac{1}{2} [(- 221 - 0.179 T) - (- 529 + 0.131 T)] = \frac{1}{2} (308 - 0.310 T)

kJ. This is zero at

T = 308/0.310 = 994

K, and negative above it.