A reaction takes place in theee steps: the rate constant are `k_(1), k_(2), and k_(3)`. The overall rate constant `k=k_(1)k_(3)//k_(2)`. If the energies of activation are `40,30, and 20 KJ mol^(-1)`, the overall energy of activation is (assuming `A` to be constant for all)

Options

A. `10`
B. `15`
C. `30`
D. `60`

Answer

c

Explanation

The overall rate constant `k=(k_(1)k_(3))/(k_(2))`
We know, `k=Ae^(-Ea//RT)`
`:. k=(k_(1)k_(3))/(k_(2))= Ae^(-(E_(a1)+E_(a3)-E_(a2))//RT)`
`=Ae^(-(40-30+20)//RT)`
`=Ae^(-30//RT)`
`:.E_(a)= 30kJ mol^(-1)`