Chemistry - Chemical Kinetics Question with Solution | TestHub

$99.9\%$ of the reaction is complete. So, if $[A{]}_0=100$, then $[A{]}_{\mathrm{t}}=100-99.9=0.1$ $$\begin{array}{rl}\mathrm{t}& =\frac{2.303}{\mathrm{k}}{\log }_{10}\frac{[\mathrm{A}{]}_0}{[\mathrm{A}{]}_4}\\ & =\frac{2.303}{0.576}{\log }_{10}\frac{100}{0.1}=\frac{2.303}{0.576}{\log }_{19}(1000)\\ & =\frac{2.303}{0.576}\times 3\\ & =11.99\approx 12\text{ minutes }\end{array}$$