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

Answer

D

Explanation

d) `A to B`
rate of reaction = `2 xx 10^(-5) mol L^(-1)s^(-1)`
Order of reaction (n) =1
rate = `k[A]^(n) = k[A]`
`k=("rate")/[A]=(2 xx 10^(-5) mol L^(-1)s^(-1))/(0.01 mol L^(-1)) = 2 xx 10^(3) s^(-1)`
`t_(1//2) = 0.693/k = 0.693/(2 xx 10^(-2)s^(-1)) = 347s`