Which one of the following is not a fossil fuel ?

Question

Accepted Answer

Option 3, Poly Ethylene Terephthalate (PET), is the correct answer because it is not a fossil fuel. PET is a type of plastic commonly used in packaging, such as plastic bottles and containers. It is a polymer made from the polymerization of ethylene glycol and terephthalic acid. While its raw materials can be derived from petroleum, PET itself is a synthetic material and not a fossil fuel.

Now, let's explain why each of the other options is incorrect:

1. **Compressed Natural Gas (CNG):** CNG is a fossil fuel. It is primarily composed of methane and is extracted from natural gas fields. Natural gas is formed from the remains of ancient marine organisms buried under layers of sediment and rock, subjected to heat and pressure over millions of years. Therefore, CNG is a fossil fuel.

2. **Liquid Hydrogen (LH):** While liquid hydrogen itself is not a fossil fuel, it is often produced using fossil fuels. The most common method of producing hydrogen is through steam methane reforming, which involves reacting natural gas (a fossil fuel) with steam. Although hydrogen can be produced using renewable resources, its association with fossil fuel-based production methods makes it distinct from PET, which is entirely synthetic.

4. **Liquified Petroleum Gas (LPG):** LPG is a fossil fuel. It is a mixture of hydrocarbon gases, primarily propane and butane, which are by-products of natural gas processing and crude oil refining. Like CNG, LPG is derived from the remains of ancient organisms and is considered a fossil fuel.

In summary, Option 3, Poly Ethylene Terephthalate (PET), is not a fossil fuel because it is a synthetic polymer, whereas the other options are either fossil fuels or closely associated with fossil fuel production.