Graph A is at 298 K and Graph B is at 398 K. At 298 K (Graph A), the equilibrium concentration of the product PQ2 is higher (approx. $0.4 mol^{-3

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6.4

Step 1: Analyze the effect of temperature on equilibrium concentrations.
Graph A is at $298 \text{ K}$ and Graph B is at $398 \text{ K}$. At $298 \text{ K}$ (Graph A), the equilibrium concentration of the product $PQ_2$ is higher (approx. $0.4 \text{ mol}\cdot\text{dm}^{-3}$) and the reactant $P_2Q$ is lower (approx. $0.1 \text{ mol}\cdot\text{dm}^{-3}$) compared to $398 \text{ K}$ (Graph B), where $[PQ_2]$ is approx. $0.