Understanding Clean Fuels

The question asks to identify an example of a clean fuel from the given options: Coke, Propane, Petrol, and Wax.

A clean fuel is a fuel that produces minimal pollution or harmful emissions when burned, especially when compared to traditional fossil fuels like coal or oil.

Evaluating the Options

Let's look at each option:

• Coke: Coke is a fuel with a high carbon content, produced by heating coal. Burning coke produces significant amounts of pollutants, including sulfur dioxide, particulate matter (soot), and carbon dioxide. It is not considered a clean fuel.
• Propane: Propane is a liquefied petroleum gas (LPG). It is often considered a relatively clean-burning fuel. When combusted completely, it produces primarily carbon dioxide and water vapor. It produces significantly less particulate matter, sulfur oxides, and nitrogen oxides compared to fuels like coal, coke, or petrol. It's widely used for heating and cooking due to its clean combustion properties.
• Petrol (Gasoline): Petrol is a complex mixture of hydrocarbons used as fuel in internal combustion engines. Burning petrol in vehicles produces various pollutants, including carbon monoxide, nitrogen oxides, unburnt hydrocarbons, and particulate matter, contributing to air pollution and smog. It is not considered a clean fuel.
• Wax: Wax, typically paraffin wax derived from petroleum, is often used in candles. While it burns, combustion can produce soot and other emissions, especially if the wick or air supply is not optimal. It is not primarily classified or used as a major energy fuel source in the same category as the others, and its combustion isn't as consistently clean as propane.

Conclusion

Comparing the combustion characteristics of the given options, Propane stands out as the cleanest burning fuel among Coke, Petrol, and Wax. It produces fewer harmful byproducts during combustion, making it a better environmental choice relative to the others listed.