Chemical Kinetics Question 59
Question: The dissociation of nitrogen pentaoxide is a first order reaction. In first 12 min, 75% of nitrogen pentaoxide is dissociated. What amount of nitrogen pentaoxide will be left behind after one hour of the start of reaction-
Options:
A) 3.01%
B) 0.21%
C) 0.098%
D) None of these
Show Answer
Answer:
Correct Answer: C
Solution:
[c] $ {t_{75 percent }}=2{t_{1/2}}\Rightarrow {t_{1/2}}=\frac{12}{2}=6\min $ N=No. of half lives in 60 min $ =\frac{60}{6}=10 $ Amount of substance left after 10 half lines $ ={{( \frac{1}{2} )}^{10}}=\frac{1}{1024} $
$ \therefore $ % of amount left $ =\frac{100}{1024}=0.098% $
