Linear and Parabolic Rate Constants

Fig. 3 Illustration of the two oxidation rate regimes. [3]

The equation d₀² + Ad₀ =B(t+t) has two important limiting conditions:

1. One limiting case occurs for long oxidation times and we get

d₀² = Bt

This is called Parabolic Law and B is the parabolic rate constant. This is diffusion-controlled case.

2. For short oxidation times we get

d₀ = B(t+t) / A

This is called Linear Law and B/A is called the linear rate constant and it is a reaction-controlled case. [3] [2]