A follows first order reaction.
`(A) rarr Product`
The concentration of `A` changes form `0.1 M` to `0.025 M` in `40 min`. Find the rate of reaction of `A` when the concentration of `A` is `0.01 M`.

Options

A. `1.73 xx 10^(-5) M//min`
B. `3.47 xx 10^(-4) M//min`
C. `3.47 xx 10^(-5) M//min`
D. `1.73 xx 10^(-4) M//min`

Answer

B

Explanation

Rate constant for the first-order reaction is given by
`k = (2.303)/(t)"log"((a)/(a-x))`
`a = 0.1M`
`(a-x) = 0.025 M`
`t = 40 min`
`:. k = (2.303)/(40)"log"(0.1)/(0.025 M)`
`= 0.0347 "min"^(-1)`
Rate `= ((d x)/(d t)) = k[A]^(1) = 0.0347 xx 0.1`
`= 3.47 xx 10^(-4) M "min"^(-1)`