The rate of the reaction A `rarr` Products at the initial concentration of `3.24 xx10^(-2)` M is nine times its rate at another initial concentration of `1.2xx10^(-3)` M. The order of the reaction is

Options

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

Answer

D

Explanation

( C) If rate at conc .` 1.2 xx10^(-2) ` M is r then
`r = k(1.2xx10^(-3))^(a)" " cdots(i) `
`9r= k(3.24xx10^(-2))^(a) " " cdots(ii)`
Dividing eq (ii) by eq. (i)
`9=((3.24xx10^(2))^(a))/((1.2xx10^(-3))^(a))=27^(a)`
or` 3^(2)=3^(3a)`
`:. 3a=2 "or" a =2//3`