For reaction `aA rarr xP`, when `[A] = 2.2 mM`, the rate was found to be `2.4mM s^(-1)`. On reducing concentration of `A` to half, the rate changes to `0.6 mM s^(-1)`. The order of reaction with respect to `A` is

Options

A. `1.5`
B. `2.0`
C. `2.5`
D. `3.0`

Answer

B

Explanation

`aA rarr xP`
Rate of reaction `= [A]a`
Order of reaction `= a`
`[A]_(1) = 2.2 mM, r_(1) = 2.4 mM s^(-1)" "`…(i)
`[A]_(2) = 2.2//2 mM, r_(1) = 0.6 mM s^(-1) = or, (2.4)/(4)`" "… (ii)
On reducing the concentration of `A` to half, the rate of reaction is decreased by four times.
Rate of reaction `= [A]^(2)`
Order of reaction `= 2`