Calculate the time required for the completion of 90% of a reaction of first order kinetics, `t_(1/2)= 44.1` minutes.

Explanation

`k = (2.303)/(t) "log" ([A]_0)/([A])`
`t = (2.303)/(k) "log" ([A]_0)/([A])`
Calculation of k
`k = (0.693)/(t_(1/2))`
`k = 0.0157 "min"^(-1)`
`t = (2.303)/(0.0157) "log" 100/40`
`t = 146.7 "min"`