An organic compound undergoes first order decomposition. If the time taken for the 60 % decomposition is 540 s , then the time required for 90 % decomposition will be is _____ s. (Nearest integer). Given : ln 10 = 2 . 3 ; log 2 = 0 . 3

Step-by-step solution

For the First order reaction, integrated rate equation can be written as follows, t = 1 k ln a 0 a t t = time k = rate   constant a 0 = intial   concentration a t = concentration   at   time   t t 1 t 2 = 1   k ln a 0 0 . 4 a 0 1   k ln a 0 0 . 1 a 0 540 t 2 = ln 10 4 ln 10 540 t 2 = log 10 - log 4 log 10 540 t 2 = 1 - 0 . 6 1 ⇒ 540 t 2 = 0 . 4 ⇒ t 2 = 540 0 . 4 = 1350 sec