Consider the reaction in chemical equilibrium:

[tex]\[
COCl_2(g) \Leftrightarrow CO(g) + Cl_2(g)
\][/tex]

Which is the correct equation for [tex]\( K \)[/tex]?

A. [tex]\[ K = \frac{\left[ COCl_2 \right]^2}{[ CO ]\left[ Cl_2 \right]} \][/tex]

B. [tex]\[ K = \frac{\left[ COCl_2 \right]}{[ CO ]\left[ Cl_2 \right]} \][/tex]

C. [tex]\[ K = \frac{\left[ CO \right]_{\left[ Cl_2 \right]}}{\left[ COCl_2 \right]} \][/tex]

D. [tex]\[ K = \frac{[ CO ]\left[ Cl_2 \right]}{\left[ COCl_2 \right]^2} \][/tex]



Answer :

To determine the correct expression for the equilibrium constant ([tex]\(K\)[/tex]) for the given chemical reaction:

[tex]\[ COCl_2(g) \Leftrightarrow CO(g) + Cl_2(g) \][/tex]

we need to consider the general form for the equilibrium constant expression, which is given by:

[tex]\[ K = \frac{[ \text{products} ]}{[ \text{reactants} ]} \][/tex]

Each concentration term is raised to the power of its stoichiometric coefficient in the balanced chemical equation. The balanced chemical equation given is:

[tex]\[ COCl_2(g) \Leftrightarrow CO(g) + Cl_2(g) \][/tex]

Here, the stoichiometric coefficients are:
- 1 for [tex]\(COCl_2(g)\)[/tex]
- 1 for [tex]\(CO(g)\)[/tex]
- 1 for [tex]\(Cl_2(g)\)[/tex]

Based on these coefficients, the equilibrium expression becomes:

[tex]\[ K = \frac{[CO][Cl_2]}{[COCl_2]} \][/tex]

Now, let's match this result with the given options:

1. [tex]\(K = \frac{\left[ COCl_2\right]^2}{[ CO ]\left[ Cl_2\right]}\)[/tex]
2. [tex]\(K = \frac{\left[ COCl_2\right]}{[ CO ]\left[ Cl_2\right]}\)[/tex]
3. [tex]\(K = \frac{\left[ CO\right][\left[Cl_2\right]}{\left[COCl_2 \right]} \)[/tex]
4. [tex]\(K = \frac{[ CO ]\left[ Cl_2\right]}{\left[ COCl_2\right]^2}\)[/tex]

The correct option is:

[tex]\[ K = \frac{[CO][Cl_2]}{[COCl_2]} \][/tex]

Thus, the correct answer is:

[tex]\(K=\frac{\left[ CO \right]\left[ Cl_2 \right]}{\left[ COCl_2 \right]}\)[/tex]

Which corresponds to option 3.