1) The rate constant for a first-order reaction is 7.0 x 10-4 s -1. If the initial concentration of reactant is 0.080 M, What is the half-life of reaction? A) 990 s B) 79.2 s C) 12375 s D) 10.10 $\times 10^{-4}$ s Answer: Option AExplanation: Given, K= 7 x 10-4 S-1 , [A]0 =0.08 M Half life (t1/2) of a first order reaction is independent of initial concentration and is given as $t_{1/2}=\frac{0.693}{k}=\frac{0.693}{7\times 10^{-4}}s=990s$
