For a first order reaction at $27^{\circ} \mathrm{C}$, the ratio of time required for $75 \%$ completion to $25 \%$ completion of reaction is

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Aicharya · Accepted Answer

For a first order reaction, $t=\frac{2.303}{\lambda} \log _{10} \frac{a}{a-x}$ Let initial amount of reactant is 100 . $\begin{aligned} \frac{t_1}{t_2}= & \frac{\log \frac{100}{100-75}}{\log \frac{100}{100-25}} \ & =\frac{\log \frac{100}{25}}{\log \frac{100}{75}} \end{aligned}$ $\begin{aligned} & =\frac{\log 4}{\log 4 / 3} \ & =\frac{\log 4}{\log 4-\log 3} \ & =\frac{2 	imes 0.3010}{2 	imes 0.3010-0.4771} \ & =\frac{0.6020}{0.1249} \ & =4.81\end{aligned}$ /

For a first order reaction at $27^{\circ} \mathrm{C}$, the ratio of time required for $75 \%$ completion to…

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