A first-order chemical reaction is observed to be 99% complete in precisely 32 minutes. What is the — Chemical Kinetics Chemistry Question

💡 Solution & Explanation

For a first-order reaction, $t = \frac{2.303}{k} \log \frac{100}{100 - \%}$. Thus, $t_{99\%} = \frac{2.303}{k} \log 100 = \frac{2.303 \times 2}{k} = 32$. For 99.9%, $t_{99.9\%} = \frac{2.303}{k} \log 1000 = \frac{2.303 \times 3}{k}$. Comparing the two: $t_{99.9\%} = \frac{3}{2} \times 32 = 48 \text{ minutes}$.