Carbon and Fossil Fuels

Correct option is (4).

Petroleum is primarily a mixture of hydrocarbons - compounds containing only hydrogen and carbon atoms. These include alkanes, cycloalkanes, and aromatic hydrocarbons. Carbohydrates contain oxygen, carbonates are salts, and carbides contain carbon-metal bonds - none are major components of crude petroleum.

Anthracite is the highest grade coal with the highest carbon content (86-97%) and energy value. It has the lowest moisture and volatile matter content, making it the cleanest-burning coal with the highest calorific value. Lignite and peat are low-grade brown coals, while bituminous is intermediate grade.

Traditional black powder (gunpowder) is a mixture of potassium nitrate (nitre/KNO3), sulfur, and charcoal in approximately 75:15:10 ratio. The charcoal provides fuel, sulfur aids combustion and lowers ignition temperature, and nitre supplies oxygen for rapid burning. TNT is a modern explosive, not part of traditional gunpowder; sand is an inert filler.

Acenaphthene is a polycyclic aromatic hydrocarbon (PAH) consisting of naphthalene with an ethylene bridge connecting positions 1 and 8. An alternative name, 1,2-dihydroacenaphthylene, emphasizes that it is a hydrogenated form of acenaphthylene. It is a constituent of coal tar.

First-generation petrochemicals are basic building blocks like ethylene, propylene, butylene, and acetylene. Surfactants are specialty chemicals, not primary petrochemicals.

This is the correct option. Dry sand cannot be used as a lubricant.

Diesel engines differ from petrol engines in three key ways: (1) No spark plugs - ignition is through compression heat, (2) Uses fuel oil (diesel) instead of petrol, (3) No carburetor - uses fuel injectors instead. All these differences combine to make diesel engines more efficient but heavier.

Graphite is the purest form of carbon among given substances.

In deflagration, the decomposition of the explosive material is propagated by a flame front, which moves slowly through the explosive material in contrast to detonation. Deflagration is a characteristic of low explosive material.

A primary explosive is an explosive that is extremely sensitive to stimuli such as impact, friction, heat, static electricity, or electromagnetic radiation. A relatively small amount of energy is required for initiation.

An oxyliquit, also called liquid air explosive or liquid oxygen explosive, is an explosive material made of a mixture of liquid air or liquid oxygen (LOX) with a suitable fuel, usually carbon (as lampblack) or some organic chemical (e.g., a mixture of soot and naphthalene), wood meal, or aluminium powder or sponge.

Gunpowder is a classical explosive mixture composed of sulfur (fuel), charcoal (carbon source), and potassium nitrate/saltpeter (nitre, oxygen source). The nitre provides oxygen for rapid combustion, charcoal is the main fuel, and sulfur lowers the ignition temperature.

Benzene is a natural constituent of crude oil, and is one of the most basic petrochemicals. Benzene is an aromatic hydrocarbon and the second [n]-annulene ([6]-annulene), a cyclic hydrocarbon with a continuous pi bond. It is also related to the functional group of aromatic hydrocarbons (arene) which is a generalized structure of benzene.