Which will not appear in the equilibrium constant expression for the reaction below? cap h sub 2 cap o g plus cap c times s long left right arrow cap h sub 2 of g plus CO times g

Pure solids are omitted from equilibrium constant expressions because their activity is constant. In this reaction, C is a solid, so it does not appear in the expression; the gaseous substances H₂O, H₂, and CO do appear. The correct choice is C.

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