after a certain pesticide compound is applied to crops its decomposition is a first order reaction with a half life of 56 days. what is the rate constan for the decomposition reacion

Rate constant = 0.01238 days⁻¹

Explanation:

The first order reaction has as general equation:

Ln[A] = -kt + Ln[A]₀

Where [A] is concentration of the reactant after time t,

k is rate constant

And [A]₀ the initial concentration of the reactant

The half-life is the time required to reach the half of the initial concentration. If [A]₀ = 1; [A] = 1/2

Replacing:

Ln[1/2] = -kt + Ln[1]

-0.693 = -k*56days

0.01238days⁻¹ = k

the answer is option a.