For the reaction `A + Brarr C +D`, if concentratiton of A is doubled without altering the concentration of B, the rate gets doubling, If the concentration of B is increased by nine times without altering the concentration of A, the rate gas tripled. The order of reaction is

Explanation

Rate `=k[A]^(m)[B]^(n)` ......(i)
`2 xx ` rate `=k[2A]^(m)[B]^(n)` .....(ii)
`3 xx ` rate `=k[A]^(m)[9B]^(n)` .....(iii)
from equations (i) & (ii), m = 1
from equations (i) & (iii), n = `(1)/(2)`
order `= m + n = 1 + ( 1)/( 2) = 3//2 `