If the rate constant for a first order reaction is k, the time (t) required for the completion of 99% of the reaction is given by :

Options

A. `t=2.303//k`
B. `t=0.693//k`
C. `t=6.909//k`
D. `t=4.606//k`

Answer

D

Explanation

The `1^(st)` order reaction
`t=(2.303)/(k)log.(a)/(1-x)`
`=(2.303)/(k)log.(100)/(100-99)=(2.303)/(k)log10^(2)`
`=(2.303)/(k)xx2xxlog10`
`=(2.303xx2)/(k)=(4.606)/(k)`