Answer: 8.1 days
Explanation:
Expression for rate law for first order kinetics is given by:
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant = x
a - x = amount left after decay process=
a) to find rate constant
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
b) for completion of one fourth of reaction
Thus after 8.1 days , one fourth of original amount will remain.