Problem

In a first order reaction the concentration of the reactant decreases from 800 mol/dm³ to 50 mol/dm³ in

2 \times 10^4

sec. The rate constant of the reaction in sec^-1 is a.

2 \times 10^4

3.45 \times 10^{-5}

1.386 \times 10^{-4}

2 \times 10^{-4}