The rate constant for a first order reaction involving compound A was found to be $0.082 \mathrm{~mi

Question

The rate constant for a first order reaction involving compound A was found to be $0.082 \mathrm{~min}^{-1}$. When the initial concentration of A is $0.15 \mathrm{~mol} /$ litre, the time required for the concentration of A to drop to 0.03 mol / litre is nearly\

Professor PC Thomas Classes · Answer

$\mathrm{k}=0.082 \mathrm{~min}^{-1}$.\ $k=\frac{2.303}{t} \log \frac{a}{a-x} \quad t=\frac{2.303}{k} \log \frac{0.15}{0.03}$\ $=\frac{2.303}{0.082} \log \frac{0.15}{0.03}=\frac{2.303}{0.082} 	imes 0.7=20 \mathrm{~min}$\