For a zero order reaction $\mathrm{A} \longrightarrow$ product. Conc. of A decreases from $0.8 \mathrm{~mol}…

For a zero order reaction $\mathrm{A} \longrightarrow$ product. Conc. of A decreases from $0.8 \mathrm{~mol} \mathrm{dm}^{-3}$ to $0.2 \mathrm{~mol} \mathrm{dm}^{-3}$ in 6 minute. What is rate constant of the reaction?
  1. $0.01 \mathrm{~mol} \mathrm{dm}^{-3}$ minute ${ }^{-1}$
  2. $1.0 \mathrm{~mol} \mathrm{dm}^{-3}$ minute $^{-1}$
  3. $0.1 \mathrm{~mol} \mathrm{dm}^{-3}$ minute $^{-1}$
  4. $1.66 \mathrm{~mol} \mathrm{dm}^{-3}$ minute ${ }^{-1}$

Solution

For a zero order reaction, $\begin{aligned} & \mathrm{k}=\frac{[\mathrm{A}]_0-[\mathrm{A}]_{\mathrm{t}}}{\mathrm{t}} \\ & =\frac{(0.8-0.2) \mathrm{mol} \mathrm{dm}^{-3}}{6 \text { minute }} \\ & =\frac{0.6 \mathrm{~mol} \mathrm{dm}^{-3}}{6 \text { minute }} \\ & \therefore \quad \mathrm{k}=0.1 \mathrm{~mol} \mathrm{dm}^{-3} \text { minute }{ }^{-1} \end{aligned}$

Asked in: MHT CET 2024 (03 May Shift 2)

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