For a radioactive decay the value of k = `2.7xx10^(-3) s^(-1)` and initial concentration is 160 moles /L. After 100s the concentration of radioactive element is :

Options

A. 76 mol /L
B. 122 mol /L
C. 50 mol /L
D. 80 mol /L

Answer

A

Explanation

(B) `k = (2.303)/(t) "log" ([A]_(0))/([A])`
`2.7xx10^(-3) = (2.303)/(100) "log" (160)/([A])`
log` (160)/([A]) = 0.1172 `
`(160)/([A])` = 1.310
`:. [A] = (160)/(1.310)= 122 .13~~ 122 ` mol /L