Which will not appear in the equilibrium constant expression for the reaction below?

Upper H subscript 2 upper o (g) plus upper C (s) double-headed arrow upper H subscript 2 (g) plus upper C upper O (g).

[H2O]

[C]

[H2]

[CO]

[C] carbon solid

Explanation:

Pure solids and liquids are never included in the equilibrium constant expression because they do not affect the reactant amount at equilibrium in the reaction, thus since your equation has [C] as solid it will not be part of the equlibrium equation.

B: [C]

Explanation:

the [C] is a solid and equilibrium constant expressions cannot have liquids or solids

i believe the answer is a.