Respuesta :
Answer:
A. Exothermic
Explanation:
Let's consider the following reaction at equilibrium.
2 NO₂(g) ⇄ N₂O₄(g)
reddish brown colorless
In order to assess the effect of temperature on the equilibrium, we need to consider Le chatelier's principle: If a system at equilibrium suffers a perturbation, it will shift its equilibrium position to counteract such perturbation.
Let's suppose the reaction is exothermic.
- If we decrease the temperature, the system will try to increase it by favoring the forward reaction to release heat. As a consequence, more colorless N₂O₄ is produced.
- If we increase the temperature, the system will try to decrease it by favoring the reverse reaction to absorb heat. As a consequence, more reddish brown NO₂ is produced.
Since it coincides with the experimental results, we can conclude that the reaction is exothermic.