Question

In a reaction , `A + B rarr` Product, rate is doubled when the concentration of `B` is doubled, and rate increases by a factor of `8` when the concentration of both the reactants (A and B) are doubled, rate law for the reaction can be written as
A. Rate `= k[A]^(2)[B]`
B. Rate `= k[A][B]`
C. Rate `= k[A][B]^(2)`
D. Rate `= k[A]^(2)[B]^(2)`

Answer 1

Correct Answer - A
Let `r = K[A]^(m)[B]^(n)`
`r_(1) = K[A]^(m)[2B]^(n)`
`r_(2) = K[2A]^(m)[2B]^(n)`
Also, `(r_(1))/(r_(2)) = 2 and (r_(2))/(r ) = 8` (Given)
Therefore `m = 2 and n = 1`
`:. r = K[A]^(2)[B]^(1)`