Question

Use of lead-free petrol or diesel is recommended to reduce the pollutants emitted by automobiles. What role does lead play?

Answer 1

Vehicles are fitted with catalytic converters which use expensive heavy metals, like platinum-palladium and rhodium, as catalysts. These catalytic converters help in the reduction of emission of poisonous gases and conversion of unburnt hydrocarbons into carbon dioxide and water.

If leaded petrol is used in such vehicles then the lead in the petrol inactivates the catalysts and causes the emission of unburnt hydrocarbons into the atmosphere which will result into air pollution.