For the reaction, `2A + B+C rarr A_(2)B+C`
The rate `= k[A][B]^(2)` with `K = 2.0 xx 10^(-6) M^(-2) s^(-1)`. Calculate the initial rate of the reaction when `[A] = 0.1M, [B] = 0.2M` and `[C] = 0.8M`. IF the rate of reverse reaction is negligible then calculate the rate of reaction after `[A]` is reduced to `0.06M`.

Options

A. `2.59 xx 10^(-9) M s^(-1)`
B. `3.89 xx10^(-9) Ms^(-1)`
C. `1.3xx10^(-9) M s^(-1)`
D. none of these

Answer

B

Explanation

Initial conc. of `[A]=0.1 M`
After sometime `[A] = 0.06 M`
[A] used up after time t (say)
`=0.1-0.06=0.04 M`
[B] used up during the same time `=(1)/(2)xx0.04 M`
`=0.02 M`
[B] after time `t=0.2-0.02=0.18 M`
Rate `=k [A] [B]^(2)`
`=(2.0xx10^(-6))(0.06)(0.18)^(2)`
`=2.0xx6xx(1.8)^(2)xx10^(-10)Ms^(-1)`
`=3.89xx10^(-9)Ms^(-1)` .