GKFix MCQ Question

What is the equilibrium constant expression for the reaction CaCO3(s) ⇌ CaO(s) + CO2(g)?

• A. Kc = [CaO][CO₂]/[CaCO₃]
• B. Kc = [CaO]/[CaCO₃]
• C. Kc = [CO₂]
• D. Kc = [CaCO₃]/[CaO]