A first order reaction is 20% complete in the 10 minutes. Calculate the time period for 75% completion of the reaction.

Explanation

`K= (2.303)/t "log " ([A]_0)/([A]) `(First Order Reaction)
Let Initial Conc.
`[A_0] = 100 `
`[A] = (100–20 = 80) `
`k = (2.303)/10 " log " 100/80`
so `K = 0.0233 "min"^(-1)`
In second
Initial Conc.
`[A_0] = 100`
`[A] = 100 – 75=25 `
`t = (2.303)/(0.0233) " log " 100/25`
`t = (2.303)/(0.0233) "log " 100/25 `
`t = 62.18 `min.