What mechanism allows catalytic converters to transform harmful gases?

Catalytic converters play a crucial role in reducing harmful emissions from vehicles, and they achieve this through a process involving chemical reactions facilitated by catalysts. Catalysts are substances that accelerate chemical reactions without undergoing any permanent change themselves. In the case of catalytic converters, they contain catalysts such as platinum, palladium, and rhodium that promote the conversion of toxic gases like carbon monoxide, nitrogen oxides, and unburned hydrocarbons into less harmful substances such as carbon dioxide, nitrogen, and water.

The chemical reactions occurring within the catalytic converter are essential for transforming these harmful gases into safer compounds. This process occurs at relatively low temperatures compared to combustion reactions, making it efficient for controlling emissions from vehicle exhaust.

The other options do not accurately describe the mechanism employed by catalytic converters. While heat can enhance some reactions, it is not the primary mechanism by which catalysts operate in this context. Physical filtration refers to the removal of particles from a gas stream but does not entail the chemical transformation of gases. Burning exhaust gases would imply combustion, which is not the function of a catalytic converter, as its purpose is to convert gases chemically rather than through combustion.