The decrease in rate of reaction brought about by the addition of a substance (inhibitor), by virtue of its effect on the concentration of a reactant, catalyst or reaction intermediate. For example, molecular oxygen and p-benzoquinone can react as "inhibitors" in many reactions involving radicals as intermediates by virtue of their ability to act as scavengers toward these radicals.
If the rate of a reaction in the absence of inhibitor is vo and that in the presence of a certain amount of inhibitor is v, the degree of inhibition (i) is given by
i = (vo - v)/vo
See also mechanism based inhibition.
