Acertain first-order reaction (a→products) has a rate constant of 9.60×10−3 s−1 at 45 ∘c. how many minutes does it take for the concentration of the reactant, [a], to drop to 6.25% of the original concentration?

In 4.81 minutes the concentration of reactant will drop to 6.25% of the original concentration.

Explanation:

Integrated rate law of first order kinetic is given as:

Where:

= Initial concentration of reactant

[A] =concentration left after time t .

k = Rate constant

We are given :

Time taken during the reaction = t=?

t = 288.86 seconds = 4.81 minutes

1 min = 60 seconds

In 4.81 minutes the concentration of reactant will drop to 6.25% of the original concentration.