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

Options

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

Answer

C

Explanation

`r = k[A]^(alpha)[B]^(beta)`…(i)
`2r = k[2A]^(alpha)[B]^(beta)` ….(ii)
`3r=k[A]^(alpha)[9B]^(beta)`….(iii)
Dividing eqn. (ii) by (i) we get
`2 = 2^(alpha)rArr alpha =1`
Dividing eqn. (iii) by eqn. (i),we get
`3=9^(beta) or 3=3^(2)beta or 2 beta = 1 or beta = 1//2`
Order of reaction `= 1+(1)/(2)=(3)/(2)`.