Final answer:
Catalytic converters in automobiles have greatly reduced the emission of carbon monoxide (CO), a by-product of the incomplete combustion of hydrocarbon fuels. The catalyst in the converters transforms CO into less harmful substances, notably carbon dioxide and water, also helping to reduce nitrogen oxides.
Step-by-step explanation:
Catalytic Converters and Pollution Reduction
The release of carbon monoxide has been greatly reduced due to the use of catalytic converters in automobiles. These devices use a catalyst, often made from platinum or other catalytically active metals, to convert carbon monoxide into carbon dioxide (CO2) and water (H2O). Alongside converting carbon monoxide, catalytic converters also reduce the emissions of nitrogen oxides, which contribute to smog and acid rain, into nitrogen (N2) and oxygen (O2).
Automobiles emit various pollutants through the combustion of hydrocarbon fuels, one of which is carbon monoxide. It is a by-product of incomplete combustion and can reduce oxygen delivery to the body's organs, posing serious health risks. Catalytic converters are effective in reducing this pollutant by catalyzing a reaction with oxygen at high temperatures, ensuring that vehicles emit fewer harmful emissions into the atmosphere.
Although sulfur dioxide (SO2) is also a significant pollutant contributing to acid rain and smog, it is not the primary target of catalytic converters. Therefore, the correct answer to the student's question is B. Carbon monoxide.