How do inhibitors stop chain reactions?

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nanoparticles: hydrogen peroxide — catalysis Nanoparticles of a gold-palladium (yellow-blue) alloy supported on acid-treated carbon (gray) directly catalyzing hydrogen peroxide formation from hydrogen (white) and oxygen (red) while shutting off unwanted hydrogen peroxide decomposition.

Inhibitors do not "stop" chemical reactions in the sense of reversing them; rather, they decrease the rate of a reaction, a process known as inhibition or negative catalysis.1

Regarding chain reactions, inhibitors function by destroying the chain carriers. In a chain reaction, highly reactive intermediates—the chain carriers—propagate the process by repeatedly reacting with other molecules. By interacting with these carriers, the inhibitor effectively terminates the sequence, preventing the reaction from continuing at its previous rate.1

Beyond terminating chain reactions, inhibition can also occur through two other primary mechanisms:
* Reactant Sequestration: The inhibitor forms a complex with a reactant, thereby reducing its effective concentration.1
* Catalyst Poisoning: The inhibitor binds to an active catalyst, forming a complex that renders the catalyst inactive.1

In all these cases, the inhibitor acts to retard the overall velocity of the chemical reaction, often at concentrations much lower than those of the reactants themselves.1