Question
A radioactive isotope having a half - life period of 3 days was received after 12 days. If 3 ~g of the isotope is left in the container, what would be the initial mass of the isotope?
BITSAT
Chemistry
Chemical Kinetics
2020
BITSAT 2020
BITSAT Chemistry Question (2020) — Solution
Options
- A. 12 ~g
- B. 36 ~g
- C. 48 ~g
- D. 24 ~g
Answer
C. 48 ~g
Step-by-step solution
Given t_ 1 / 2 =3 Total time T =12 No. of half lives (n)= 12 3 =4 ( 1 2 )^ n = N N _ o ( 1 2 )^ 4 = 3 ~N 3 ~N = 1 16 N=48
Related: Chemistry — Chemical Kinetics · All PYQ Banks