Answer: 0.0345 sec
Explanation:
Rate law says that rate of a reaction is directly proportional to the concentration of the reactants each raised to a stoichiometric coefficient determined experimentally called as order.
k= rate constant =
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
a - x = amount left after decay process
for completion of 20 % of reaction
The time taken for the concentration of to decrease to 20% to its natural value is 0.0345 sec