Question

Catalytic poisoners act by:

• A. coagulating the catalyst
• B. getting adsorbed on the active centres on the surface of catalyst
• C. chemical combination with any one of the reactants
• D. none of the above

Answer 1

The correct option is B getting adsorbed on the active centres on the surface of catalyst

Catalyst poisoning refers to the effect that a catalyst can be 'poisoned' if it reacts with another compound that bonds chemically to its active surface sites.

This has two effects. The total number of catalytic sites or the fraction of the total surface area that has the capability of promoting reaction always decreases and the average distance that a reactant molecule must diffuse through the pore structure before undergoing reaction may increase.

Poisoned sites can no longer accelerate the reaction with which the catalyst was supposed to catalyze. Hence, catalytic poisons act by getting adsorbed on the active centres on the surface of the catalyst.