Study the reaction.
2A(?) + B(g) ⇌ A2B(g)
Both B and A2B are gases. When the reaction vessel is compressed, the equilibrium position does not change.
What conclusion can we draw about the state of “A” from this data?
A. "A" must be a gas because, if it were not, the equilibrium would shift toward the liquid or solid to relieve the pressure
B. "A" cannot be a gas because two gases cannot interact with each other due to assumptions of the ideal gas law
C. "A" must be a gas because only gases can react with other gases: the forward reaction would not occur otherwise
D. "A" cannot be a gas because, if it were, the equilibrium would shift toward the products to relieve the pressure.
C?
Nope, not C. If A were a gas, then compressing would affect the left side (more gasses) shifting the reaction to the product side.
C is incorrect
increasing pressure does not shift the equilibrium, so the gas volumes are equal on both sides of the equation ... B and A2B
... if A were a gas, the volumes would not be equal
Yes, the correct conclusion we can draw about the state of "A" from this data is that "A" must be a gas because only gases can react with other gases. Therefore, the forward reaction would not occur otherwise. So, the correct answer is C.
To determine the conclusion about the state of "A" from the given data, we need to consider the effect of compressing the reaction vessel on the equilibrium position.
When the reaction vessel is compressed, the pressure inside the vessel increases. However, according to Le Chatelier's principle, if the equilibrium position does not change upon compression, it suggests that the reaction is not affected by changes in pressure.
Based on this information, we can conclude that "A" must be a gas. If "A" were a liquid or a solid, the equilibrium would shift towards the liquid/solid side to relieve the increased pressure. But since the equilibrium does not change, it implies that both reactant and product are gases, in this case, "B" and "A2B", respectively.
Therefore, the correct conclusion is:
A. "A" must be a gas because, if it were not, the equilibrium would shift toward the liquid or solid to relieve the pressure.