Carbon and Fossil Fuels

A good fuel should have high calorific value, should be cheap, should not cause any pollution and should be easy to transport.

 the major components of all kerosenes are branched and straight chain alkanes and naphthenes (cycloalkanes), which normally account for at least $70\%$ by volume

Ignition temperature is the lowest temperature at which a substance catches fire. Among the choices, LPG is a highly volatile gas with a very low ignition temperature compared to solids like coal or liquids like kerosene.

The producer gas is a mixture of nitrogen and carbon monoxide. Two thirds by volume is nitrogen and one third by volume is carbon monoxide. Carbon monoxide is combustible gas in the mixture. Nitrogen is non-combustible. producer gas is not considered as good fuel because it contains Nitrogen which does not burn.

An ideal gas must possess high calorific value, must have a moderate rate of combustion and must be easily available. The calorific values of coal, petrol, LPG are quite less than an ideal gas. The molecules present in an ideal gas obeys the gas laws and follows the Newtons laws of motion.

LPG (Liquefied Petroleum Gas) is considered a cleaner fuel compared to petrol or mineral oil because it produces fewer particulate emissions and less carbon monoxide upon combustion. Methane is also a clean fuel, but LPG is the standard answer in this context for domestic clean fuel usage.

Ideal fuel shows the following characteristics:

• It should be  less expensive,
• It should be easily  available,
• It should produce a large amount of heat,
• It can be  transported  easily
• It has high calorific value.
• It should  burns easily in air at a moderate rate.

Hence option D is correct.

C.N.G (compressed natural gas) is a cleaner fuel because it causes less pollution by emitting fewer pollutants like carbon dioxide, carbon monoxide, sulphur dioxide, nitrogen dioxide, particulate matter, unburned hydrocarbons etc.

Ideal fuel has high calorific value. This ensures that more amount of heat energy is released from the combustion of unit mass of fuel. In other words, a fuel with high calorific value is better than a fuel having low calorific value.

LPG is a better domestic fuel than wood because of several reasons. Unlike wood, LPG burns without smoke. This makes the life of housewives more comfortable and they do not have to worry about blackening of pots and pans. Moreover, use of LPG as domestic fuel also rules out the chances of getting respiratory disorders which may happen when someone uses wood as kitchen fuel. Storage and transportation of LPG is easier compared to that of wood.

Solid fuel refers to various types of solid material that are used as fuel to produce energy and provide heating, usually released through combustion. Solid fuels include wood, charcoal, peat, coal, Hexamine fuel tablets, and pellets made from wood, corn, wheat, rye and other grains.

Compressed natural gas (CNG) (methane stored at high pressure) can be used in place of gasoline (petrol), Diesel fuel and propane/LPG. CNG is made by compressing natural gas (which is mainly composed of methane), to less than 1 percent of the volume it occupies at standard atmospheric pressure. 

Biogas can be considered as an ideal gas because it has an appropriate calorific value, easily processed from cow dung and other waste materials. It is environment friendly and burns smoothly without any residues. It contains negligible non-volatile materials.

Compressed natural gas (CNG) (methane stored at high pressure) can be used in place of gasoline (petrol), Diesel fuel and propane/LPG. CNG is made by compressing natural gas (which is mainly composed of methane, CH4), to less than 1 percent of the volume it occupies at standard atmospheric pressure. 

A good fuel produces a huge amount of heat on burning, does not produce a lot of smoke, and is easily available.