What is the Difference Between Leaded Petrol and Unleaded Petrol?

The main difference between leaded and unleaded petrol lies in the presence of the additive tetraethyl lead. Leaded petrol contains this additive, which increases its octane rating and reduces knock in car engines. In contrast, unleaded petrol does not contain tetraethyl lead and instead uses other additives to raise its octane level and boost performance.

A brief comparison of leaded and unleaded petrol:

• Leaded Petrol:
• Contains tetraethyl lead, which raises its octane level and reduces engine knock.
• Lead is a pollutant that can harm the environment and human health.
• Phased out in most countries due to its harmful effects.
• Unleaded Petrol:
• Does not contain tetraethyl lead.
• Uses other additives, such as ethanol, to raise its octane level and increase performance.
• Less damaging to the environment and human health compared to leaded petrol.

The switch from leaded to unleaded petrol was primarily due to the negative health and environmental effects of lead. Car manufacturers have since adapted to the use of unleaded petrol by installing catalytic converters in exhaust emission control devices. While leaded petrol may still be used in some older vehicles and specific applications like aviation, race cars, and marine engines, it has been largely replaced by unleaded petrol in consumer vehicles.

Comparative Table: Leaded Petrol vs Unleaded Petrol

The main difference between leaded petrol and unleaded petrol is the presence of lead additives in leaded petrol and the absence of such additives in unleaded petrol. Here is a table highlighting the differences between the two:

Leaded petrol was once the standard fuel for cars, containing lead as an octane booster to prevent engine knock. However, lead is a toxic pollutant, and its use in petrol has been largely phased out due to health and environmental concerns. Unleaded petrol, on the other hand, does not contain lead and is the preferred choice for most motorists today.