Question – If the initial concentration of cyclopropane is 0.0501 M. What will the cyclopropane concentration after 352 minutes.
The reaction is first order. Rate constant = 3.36 x 10-5 sec-1
Solution-
For first order reaction,
K = (2.303 /t )log [A0]/ [At]
K = 3.36 x 10-5 sec-1
t= 352 minutes = 352 x 60 sec
t = 21120 sec
[A0] = 0.0501 M
3.36 x 10-5 =[ 2.303/21120] log 0.0501 /[At]
3.36 x 10-5 = (1.09 x 10-4) log 0.0501 /[At]
log 0.0501 /[At] = 3.36 x 10-5 / 1.09 x 10-4
log 0.0501 /[At] = 0.308
0.0501 /[At] = antilog 0.308
= 2.032
[At] = 0.0501/ 2.032 = 0.0246 M
cyclopropane concentration after 352 minutes will be 0.0246 M Ans.