Question

Fe and FeO are in equilibrium with a gas mixture of composition 71.8% CO–28.2% CO2 at 1273 K. Which of the two solid phases disappears if the composition of the gas is held constant and the temperature of the system is decreased?

Answer 1

we have

For eq. (2), The change in G is

similarly for eq. (3)

Subtracting eq.(3) from eq.(2).we get for eq.(1)

We see that as T decreases, becomes more negative.

Since the reaction will go in the forward direction,

  will increase

while

  will decrease and disappear.