Answer :
Half life period for the reaction where deduction of mass takes places is 8 days.
What is half life?
Half life period of any reaction is that time where half concentration of reactant get converted into product.
Here we can calculate the half life through the below equation:
[tex]$m = {m^'} \times {\left( {\frac{1}{2}} \right)^{\frac{t}{T}}}$[/tex]
where, m' = initial mass of iodine = 80g
m = remaining mass = 2.5g
t = taken time = 40 days
T = half life
By putting this all value in above equation, we get
[tex].$\begin{array}{l}2.5 = 80 \times {\left( {\frac{1}{2}} \right)^{\frac{{40}}{T}}}\\\frac{{2.5}}{{80}} = {\left( {\frac{1}{2}} \right)^{\frac{{40}}{T}}}\\{\left( {\frac{1}{2}} \right)^5} = {\left( {\frac{1}{2}} \right)^{\frac{{40}}{T}}}\\5 = \frac{{40}}{T}\\T = 8\end{array}$[/tex]
Hence, half life period of this reaction is 8 days.
To learn more about half life time, do visit the given link:
https://brainly.com/question/2320811