The rate for reaction $2 \mathrm{~A}+\mathrm{B} \rightarrow$ product is $6 \times 10^{-4} \mathrm{~mol}…

The rate for reaction $2 \mathrm{~A}+\mathrm{B} \rightarrow$ product is $6 \times 10^{-4} \mathrm{~mol} \mathrm{dm}^{-3} \mathrm{~s}^{-1}$ Calculate the rate constant if the reaction is first order in $\mathrm{A}$ and zeroth order in B. $[\operatorname{Given}[\mathrm{A}]=[\mathrm{B}]=0.3 \mathrm{M}]$
  1. $1 \times 10^{-3} \mathrm{~s}^{-1}$
  2. $2 \times 10^{-3} \mathrm{~s}^{-1}$
  3. $3 \times 10^{-3} \mathrm{~s}^{-1}$
  4. $4 \times 10^{-3} \mathrm{~s}^{-1}$

Solution

$\begin{aligned} & \text { Rate }=\mathrm{k}[\mathrm{A}] \\ & \therefore \quad \mathrm{k}=\frac{\text { Rate }}{[\mathrm{A}]}=\frac{6 \times 10^{-4} \mathrm{~mol} \mathrm{dm}^{-3} \mathrm{~s}^{-1}}{0.3 \mathrm{~mol} \mathrm{dm}^{-3}}=2 \times 10^{-3} \mathrm{~s}^{-1} \\ & \end{aligned}$

Asked in: MHT CET 2023 (14 May Shift 1)

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