Question

21. A first order reaction takes 40 min for 30% decomposition. Calculate t1/2 for first order reaction ((log 7
= 0.8451, log 10 = 1)​

Answer 1

Answer:

77.7 minutes is the answer

Explanation:

Let a M be the initial concentration. After 40 minutes, the concentration is a−30a/ 100  =0.70a.

k=  2.303/t log [A])  − / [A]

k= 2.303/40  log a/ 0.70a

k=8.92×10^−3 /min

The half life period, t  1/2  = 0.693/k= 0.693/8.92×10 ^-3/min=77.7 minute

hope this helps u