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

Options

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

Answer

B

Explanation

(A) `k= (2.303)/(20) "log" (100)/(81) `
`k = (2.303)/(x) "log" (100)/(81)`
since (i) = (ii)
`(2.303)/(20)"log" (100)/(90) = (2.303)/(x) "log" (100)/(81)`
`x= (20 "log"(100)/(81))/("log" (100)/(90))`
`= (20xx0.0915)/(0.046) = 40 ` min