Cambridge O Level Chemistry · Syllabus 5070 · Chemistry of the Environment
Catalytic Converter
What is Catalytic Converter?
A device fitted to the exhaust system of a vehicle that converts harmful gases in the exhaust into less harmful products. Carbon monoxide and nitrogen monoxide react over the catalyst to give carbon dioxide and nitrogen. The catalyst increases the rate of the reaction and is not used up, so it goes on working for the life of the vehicle.
This definition is part of the Chemistry of the Environment chapter in Cambridge O Level Chemistry.
Common mistakes with Catalytic Converter
- “Catalytic converters remove sulfur dioxide from the exhaust.” Defect The control is attached to the wrong pollutant. Chemistry Converters deal with harmful gases such as carbon monoxide and oxides of nitrogen. Sulfur dioxide is controlled by low-sulfur fuels or flue gas desulfurisation with calcium oxide. Repair Converter → vehicle; low-sulfur fuel and desulfurisation → power station. Transfer Write the desulfurisation equation. \(\mathrm{CaO + SO_2 \rightarrow CaSO_3}\).
- “A catalytic converter turns harmful gases into harmless ones.” Defect One word too strong. Chemistry Nitrogen is benign, but carbon dioxide contributes to global warming. The syllabus wording is less harmful products. Repair Write “less harmful” and, if there is room, name the residual concern. Transfer Does fitting a converter reduce carbon dioxide from a car? No — it increases it slightly, by oxidising carbon monoxide.
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