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

b) For `M to N`
`r=k[M]^(x)`
As M becomes double, r becomes eight times.
`therefore 8r = k[2M]^(x)`
`(8r)/r= ([2M]^(x))/([M])`
`(2)^(3) = (2)^(x)` or x=3