For a first-order reaction `A rarr B` the reaction rate at reactant concentration of `0.10 M` is found to be `2.0 xx 10^(-5) "mol" L^(-1) s^(-1)`. The half-life period of the reaction is

Options

A. 300 s
B. 30 s
C. 220 s
D. 347 s

Answer

D

Explanation

`r=k xx[A] rArr 2xx10^(-5) =k xx0.01 rArr k=2xx10^(-3)`
Half life, `t_(1//2) =(0.693)/(2xx10^(-2))=(693)/(2)" sec "~~ 347` sec.