What is the equilibrium constant expression for the given reaction?

Answer: Option (c) is the correct answer.
Explanation:
At equilibrium the relationship expressed between the amounts of concentration of products and reactants in a reversible chemical reaction is known as equilibrium constant.
The concentration of solids and liquids is considered equal to 1 in equilibrium constant.
For example, in the given reaction [tex]CaCO_{3}(s) \rightleftharpoons CaO(s) + CO_{2}(g)[/tex]
Therefore, its equilibrium constant will be as follows.
[tex]K_{eq} = \frac{[CO_{2}][CaO]}{CaCO_{3}}[/tex]
Here concentration of [tex]CaCO_{3}[/tex] and CaO is 1 as these are solids.
Thus, equilibrium constant expression will be as follows.
[tex]K_{eq} = [CO_{2}][/tex]