Chemical Kinetics Question 336
Question: A radioactive isotope having a half - life period of 3 days was received after 12 days. If 3g of the isotope is left in the container, what would be the initial mass of the isotope-
Options:
A) 12g
B) 36g
C) 48g
D) 24g
Show Answer
Answer:
Correct Answer: C
Solution:
[c] Given $ {t_{1/2}}=3 $ Total time T =12 No. of half lives $ ( n )=\frac{12}{3}=4 $
$ {{( \frac{1}{2} )}^{n}}=\frac{N}{N_{o}}\therefore {{( \frac{1}{2} )}^{4}}=\frac{3}{N} $
$ \frac{3}{N}=\frac{1}{16} $ N=48 g
