A subtance `'A'` decomposes by a first-order reaction starting initially with `[A] = 2.00 m` and after `200 min` `[A] = 0.15 m`. For this reaction what is the value of `k`

Options

A. `1.29 xx 10^(-2) "min"^(-1)`
B. `2.29 xx 10^(-2) "min"^(-1)`
C. `3.29 xx 10^(-2) "min"^(-1)`
D. `4.40 xx 10^(-2) "min"^(-1)`

Answer

A

Explanation

Given `A(a) = 2.00 m, t = 200 min` and `(a-x) = 0.15 m` we know
`k = (2.303)/(t) "log"(a)/(a-x) = (2.303)/(200) "log"(2.00)/(0.15)`
`= (2.303)/(200) xx (0.301 + 0.824) = 1.29 xx 10^(-2) "min"^(-1)`