In a first order reaction the concentration of the reactant decreases from 0.8 to 0.4 M in 15 minutes . The time taken for the concentration to change from 0.1 M to 0.025 M is :

Options

A. a) 7.5 mins
B. b) 15 mins
C. c) 30 mins
D. d) 60 mins

Answer

C

Explanation

(C ) `t_(1//2) ` is 15 min
`:.` Conc . Reduces from 0.1 to 0.025 M in `2t_(1//2)`
i.e 30 min