Tutoring chemistry, reaction order is a topic. The tutor mentions the idea of zeroth-order reaction, with an example.
A zeroth-order reaction is one that proceeds at the same rate even if the concentration of reactant is increased. Of course, there must be sufficient reactant for the reaction to happen at its baseline rate. Having met that condition, however, increasing the reactant concentration does not increase the rate of a zeroth-order reaction.
Zeroth-order reaction is not necessarily an intuitive idea, but here’s an example: the liver’s processing ability of alcohol is often described as about an ounce per hour, regardless of how much the person consumes. If true, then the liver’s processing of alcohol is zeroth order: its rate does not increase even if more alcohol (the reactant) is introduced.
Mortimer, Charles E. Chemistry, sixth edition. Belmont: Wadsworth Publishers, 1986.Oracle Tutoring by Jack and Diane, Campbell River, BC.