Which of the following is the equilibrium constant expression for the reaction?2NO(g) + O2(g) → 2NO2(g)None of the choices are correct.

To determine the equilibrium constant expression for the given reaction, we follow the steps below:

1. ### Break Down the Problem

We need to write the expression for the equilibrium constant $K_c$ for the following reaction: $2 \text{NO}(g) + \text{O}_2(g) \rightleftharpoons 2 \text{NO}_2(g)$

2. ### Relevant Concepts

The equilibrium constant expression $K_c$ for a general reaction: $aA + bB \rightleftharpoons cC + dD$ is given by: $K_c = \frac{[C]^c[D]^d}{[A]^a[B]^b}$

3. ### Analysis and Detail

Applying this to our reaction:

• $A$ is NO with a coefficient of 2, giving $[NO]^2$
• $B$ is $O_2$ with a coefficient of 1, giving $[O_2]^1$
• $C$ is $NO_2$ with a coefficient of 2, giving $[NO_2]^2$

Thus, the equilibrium constant expression for this reaction is: $K_c = \frac{[\text{NO}_2]^2}{[\text{NO}]^2[\text{O}_2]}$

4. ### Verify and Summarize

This expression accurately reflects the stoichiometry of the given reaction. Since we derived it based on the standard formulation, we can verify that the structure is consistent with equilibrium expressions.

Final Answer

The equilibrium constant expression for the reaction $2\text{NO}(g) + \text{O}_2(g) \rightleftharpoons 2\text{NO}_2(g)$ is: $K_c = \frac{[\text{NO}_2]^2}{[\text{NO}]^2[\text{O}_2]}$