The time taken for 10 % completion of a first order reaction is 20 minutes. Then for 19 % completion, the reaction will take

Options

A. 40 min
B. 60 min
C. 30 min
D. 50 min

Answer

A

Explanation

`t = (2.303)/(k)"log"(a)/(0.10a)`
`:. 20=(2.303)/(k)"log"(a)/(a-0.10a)`
or `20 =(2.303)/(k)"log" (10)/(9)`
In s2nd case `t = (2.303)/(k) "log"(a)/(a-0.19 a)`
`(2.303)/(k)"log"(100)/(81)`
`=(2.303)/(k)log((10)/(9))^(2)`...(ii)
Eqn (ii)//Eqn (i) gives.