For the first-order reaction `T_(av)` (average life), `T_(50)` and `T_(75)` in the increasing order are :

Options

A. `t_(50)lt t_(av) lt t_(75),`
B. `t_(50)lt t_(75) lt t_(av),`
C. `t_(av)lt t_(50) lt t_(75),`
D. `t_(av)=t_(50) lt t_(75),`

Answer

A

Explanation

`t_(av) = (1)/(k) = (1)/(0*693//t_(1//2)) = (t_(1//2))/(0*693) = 1*44 t_(50%)`
Also, we know that `t_(75%) = 2 xx t_(50%)`
Hence, `t_(50%) lt t_(av) lt t_(75%)`