In a first order reaction, the concentration of the reactant is reduced from $0.6 \mathrm{~mol}…

In a first order reaction, the concentration of the reactant is reduced from $0.6 \mathrm{~mol} \mathrm{~L}^{-1}$ to $0.2 \mathrm{~mol} \mathrm{~L}^{-1}$ in $5 \mathrm{~min}$. What is the rate constant of the reaction? $(\log 3=0.4771)$
  1. $0.219 \mathrm{~min}^{-1}$
  2. $0.325 \mathrm{~min}^{-1}$
  3. $0.421 \mathrm{~min}^{-1}$
  4. $0.522 \mathrm{~min}^{-1}$

Solution

Given, $ \begin{aligned} t & =5 \text { minute } \\ A^{\circ} & =0.6 \mathrm{~mol}^{-1} \\ A & =0.2 \mathrm{~mol}^{-1} \\ k & =\frac{2.303}{t} \log \frac{A^{\circ}}{A} \\ & =\frac{2.303}{5} \log \frac{0.6}{0.2}=0.219 \mathrm{~min}^{-1} \end{aligned} $

Asked in: AP EAMCET 2022 (06 Jul Shift 2)

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