Question

29. In a first order reaction, the concentration of the reactant decreases from 0.8 M to 0.4 M in
15 minutes. The time taken for the concentration to change from 0.1 M to 0.025 M is
(a) 15 min (b) 7.5 min (c) 60 min
(d) 30 min​

Answer 1

(d) I think because 0.8 to 0.4 M in 15 mins then 0.1 to 0.025 is 30 mins

Answer 2

Answer:

if it is from initial

time taken from

0.8 to o.4  is 15m

0.4 to 0.2 is 15m

0.2 to 0.1 is 15m

0.1 to 0.05 is 15m

0.05 to 0.025 is 15m

so, time taken from 0.1M to 0.025M is 30minutes