For the elementary reaction `MrarrN`, the rate of disappearance of `M` increases by a factor of `8` upon doubling the concentration of `M`. The order of the reaction will respect to `M` is

Options

A. `4`
B. `3`
C. `2`
D. `1`

Answer

B

Explanation

`r_(1) = K[M]^(x)` …(i)
`8r_(1) = k[2M]^(x)` …(ii)
`rArr (1)/(8) = ((1)/(2))^(x) rArr ((1)/(2))^(3) = ((1)/(2))^(x) rArr x = 3`