Answer:
c. remain constant.
Explanation:
The half life is defined as the time at which the reactant's concentration reduced to half.
The formula for the half life for a first order kinetic reaction is:
[tex]t_{1/2}=\frac {ln\ 2}{k}[/tex]
Where,
[tex]t_{1/2}[/tex] is the half life
k is the rate constant.
As seen from the formula the half life for a first order reaction is independent of the reactant's concentration.
So, it will remain constant on any change of the reactant's concentration.
