Rate constant of a reaction with a virsus is `3.1 xx 10^(-4) s^(-1)`. Time required for a virus to become `75%` inactivated is

Options

A. `17.5 min`
B. `40 min`
C. `74.5 min`
D. `30 min`

Answer

C

Explanation

Virsus inactivation follows first order kinetics based on unit of `k(s^(-1))`.
`t_(50) = (0.693)/(k) = (0.693)/(3.1 xx 10^(-4)s^(-1)) = 2235s`
`:. t_(75) = 2 xx t_(50) = 4470s = (4470)/(60) = 74.5 min`