Answer:
16.6 days will it take for 90% of the iodine - 131 in a 0.500 M solution of this substance to decay to Xe-131.
Explanation:
I- 131 → Xe - 131 + e⁻
the decay process follow first order kinetics
given, decay constant (λ)= 0.138 d⁻¹
[tex]t=\frac{2.303}{Decay constant} log\frac{N_{0} }{N}[/tex]----------------------------------(1)
No → Initial amount of I- 131 = 0.5 (M)
[tex]N= Remaining=0.5 - 0.5 X \frac{90}{100} =0.05(M)[/tex]
from equation 1
[tex]t =\frac{2.303}{0.138} log\frac{0.5}{0.05}[/tex]
[tex]=\frac{2.303}{0.138}days\\ \\=16.6days[/tex]
∴ 16.6 days will it take for 90% completion.
