Sodium hypochlorite (NaClO) is used as a common disinfectant. It decomposes in a first-order process with a rate constant of 0.10 s^-1. How long would it take for an initial concentration of 0.20 M to decrease to 0.07 M ?

Question

Quizplus · Accepted Answer

The first-order rate law is given as:

rate = k [NaClO]

where k is the rate constant.

The integrated rate law for a first-order reaction is:

ln ([NaClO]t/[NaClO]0) = -kt

where [NaClO]t is the concentration at time t and [NaClO]0 is the initial concentration.

Plugging in the values given in the problem, we get:

ln (0.07/0.20) = -0.10t

Solving for t, we get:

t = 10.5 s

Sodium Hypochlorite (NaClO) Is Used as a Common Disinfectant