Final answer:
Adding more SO₃ to the reaction SO₂(g) + NO₂(g) ⇌ NO(g) + SO₃(g) would shift the equilibrium towards the left, resulting in the formation of more SO₂ and NO₂. This is a direct application of Le Chatelier's principle to a change in concentration of a product at equilibrium.
Step-by-step explanation:
When SO₃ (sulfur trioxide) is added to the equilibrium reaction SO₂(g) + NO₂(g) ⇌ NO(g) + SO₃(g) + heat, the system will respond according to Le Chatelier's principle, which states that a system at equilibrium will try to counteract any changes made to it. In this case, by adding more SO₃, the equilibrium will shift towards the left to reduce the concentration of SO₃ by producing more reactants, SO₂ and NO₂. Consequently, the correct answer is 3) More NO₂ and SO₂ would form. This is an example of how equilibrium shifts when there is a change in the concentration of a product.
It's important to connect this with related equilibrium reactions, such as the formation of NO from N₂ and O₂, where adding more O₂ would shift the equilibrium towards the production of more NO. Similarly, the reaction of S(s) and O₂(g) to form SO₂(g), or the combination of H₂(g) with Br₂(g) to form HBr(g), are cases where changes in concentration, pressure, volume, or temperature would also affect the equilibrium position.
The case of the reaction 2SO₂(g) + O₂(g) ⇌ 2SO₃(g) illustrates that the equilibrium constant (K) may change when the temperature is altered because this affects the rates of the forward and reverse reactions differently. This is unlike changes in concentration or pressure, which do not affect the value of K.