A first order reaction is `15%` complete in 20 minutes. How long will it take to be `60%` complete.

Answer

`112.7" min"`

Explanation

`k=(2.303)/(20" min")log""(100)/(100-15)=(2.303xx0.0706)/(20)min^(-1)`
`t=(2.303)/(k)log""(100)/(100-60)=(2.303xx20)/(2.303xx0.0706)log""(100)/(40)=(20)/(0.0706)xx0.3979=112.7" min"`