The rate constant for a first order reaction Is 90 `s^-1` .How much time will it take to reduce the concentration of the reactant to `1/20^(th)` of its Initial value ?

Explanation

For the first order Reaction
`t = (2.303)/k log "" ([A_0])/([A])`
`k = 90s^(-1), [A] = ([A]_0)/20 rArr So t = 2.303/90 xx log ([A_0])/([A_0]//20)`
t = 0.033 m
` t = 3.3 xx 10^(-2) s`.