Some times a reacant undergoes chemical/radioactive changes following two or more different paths to yield two or more different produces respectively. Such reactions are called parallel path reactions. If `K_(1)` and `K_(2)` are rate constans for the reaction of `A` follwing two parallel paths, then

Then `K_(av) = K_(1) + K_(2)`
For
if `E_(1)` and `E_(2)` are energy fo activations, then
A. `E_(“Total”) = E_(1) + E_(2)`
B. `E_(“Total”) = E_(1) – E_(2)`
C. `E_(“Total”) = K_(1) E_(1) + K_(2)E_(2)`
D. `E_(“Total”) = (K_(1) E_(1) + K_(2)E_(2))/(K_(1) + K_(2))`

Then `K_(av) = K_(1) + K_(2)`
For

A. `E_(“Total”) = E_(1) + E_(2)`
B. `E_(“Total”) = E_(1) – E_(2)`
C. `E_(“Total”) = K_(1) E_(1) + K_(2)E_(2)`
D. `E_(“Total”) = (K_(1) E_(1) + K_(2)E_(2))/(K_(1) + K_(2))`
Correct Answer – `d`
`K_(av) = K_(1) + K_(2)`
`A_(T)e^(-E_(T)//RT^(2)) = A_(1) e^(-E_(1)//RT^(2)) + A_(2) e^(-E_(2)//RT^(2))` ….(1)
Differentiating eqn. (1)
`A_(T). (E_(T))/(RT).e^(-E_(T)//RT^(2)) = A_(1). (E_(1))/(RT).e^(-E_(1)//RT^(2)) + A_(2) (E_(2))/(RT) e^(-E_(2)//RT^(2))`
`K_(av) (E_(T))/(RT) = (K_(1)E_(1))/(RT) + (K_(2) E_(2))/(RT)`
`(K_(1) + K_(2)) (E_(T))/(RT) = (K_(1)E_(1))/(RT) + (K_(2) E_(2))/(RT)`
`:. E_(T) = (K_(1) E_(1) + K_(2) E_(2))/(K_(1) + K_(2))`