Question #44717

Solid $\ce{A}$ (Molar mass = $150 \text{ g mol}^{-1}$) is added in excess to a solvent at $298 \text{ K}$. The saturation solubility of $\ce{A}$ in this solvent is $3.0 \text{ g L}^{-1}$. To this saturated solution, reactant $\ce{B}$ is added such that its initial concentration is $0.50 \text{ mol dm}^{-3}$. The overall reaction is: $\ce{3A(aq) + 2B(aq) -> P(aq)}$ The proposed mechanism for this reaction is: Step 1: $\ce{2A(aq) + B(aq) ->[k_1] I(aq)}$ (Slow) Step 2: $\ce{I(aq) + A(aq) + B(aq) ->[k_2] P(aq)}$ (Fast) Given the rate constant for the slow step is $k_1 = 4.0 \times 10^{-2} \text{ dm}^6 \text{ mol}^{-2} \text{ s}^{-1}$, what is the initial rate of disappearance of $\ce{B(aq)}$ in $\text{mol dm}^{-3} \text{ s}^{-1}$?