The rate constant of a first-order reaction is 10–2 min–1. The half-life period of the reaction is:

693 min 69.3 min 6.93 min 0.693 min

69.3 min

For First order reactions, \(k =\frac{0.693}{t_{1/2}}\) Given, \(k = 10^{−2} \text{ min}^{−1}\) \(∴ k = \frac{0.693}{t_{1/2}}\) or, \( t_{1/2} = \frac{0.693}{10^{−2}}\) or, \(t_{1/2} = 69.3 \text{ min}\)