SO₂(g) + NO₂(g) ⇌ SO₃(g) + NO(g)

This reaction represents the formation of sulfur trioxide (SO₃) and nitric oxide (NO) from sulfur dioxide (SO₂) and nitrogen dioxide (NO₂).

To find the equilibrium constant (K) for this reaction, you need to know the equilibrium concentrations of all the reactants and products.

Here's how to determine the equilibrium constant:

1. Write the equilibrium expression: For the given reaction, the equilibrium constant (K) is defined as:

K = ([SO₃][NO]) / ([SO₂][NO₂])

where the square brackets indicate the equilibrium concentrations of each species.

2. Determine the equilibrium concentrations: You would typically obtain these values experimentally. This might involve measuring the concentrations of each species at equilibrium using techniques like spectrophotometry or gas chromatography.

3. Substitute the equilibrium concentrations into the equilibrium expression: Once you have the equilibrium concentrations of all the reactants and products, you can plug them into the expression above to calculate K.

Important Notes:

* Temperature dependence: The equilibrium constant (K) is temperature-dependent. A change in temperature will shift the equilibrium position and change the value of K.

* Standard conditions: If you're looking for a specific value for the equilibrium constant under standard conditions (298 K and 1 atm), you can often find it in tables of thermodynamic data.

Let me know if you have specific equilibrium concentrations for this reaction. I can then help you calculate the equilibrium constant.