2C(s)+O2(g)⇌2CO(g) ;Keq2=10−3 ...(i)
CO2(g)⇌C(s)+O2(g) Keq7=102 ...(ii)
Adding (i) and (ii), we get
C(s)+CO2(g)⇌2CO(g) ;Keq3=10−1=X ...(iii)
Again, 2CO(g)⇌2C(s)+O2(g) Keq5=103 ...(iv)
2C(s)+2O2(g)⇌2CO2(g) Keq6=10−4 ...(v)
Adding (iv) and (v) we get,
2CO(s)+O2(g)⇌2CO2(g) Keq4=10−1=Y
Hence, XY=1.