Carbon and Fossil Fuels

Burning kerosene oil is classified as rapid combustion because it occurs at a fast rate when the fuel is ignited, producing heat and light steadily. Option A correctly identifies this as rapid combustion. Spontaneous combustion (B) occurs without external ignition. Explosion (C) involves sudden, violent combustion with pressure waves. Kerosene burning is a controlled, steady burning process, not an explosion.

LPG (liquefied petroleum gas) used as a domestic fuel has a high calorific value. The ignition temperature of this fuel is reasonably low. It is a mixture of hydrocarbons.

The cooking gas used as a fuel for domestic purposes is liquified petroleum gas.

Primary fuels or primary energy sources are dense sources of primary energy found as natural resources. Primary fuels are fuels that are found in nature and can be extracted, captured, cleaned or graded without any sort of energy conversion or transformation process.

In villages and rural areas, wood is the most commonly used naturally occurring solid fuel for cooking and heating. Option B correctly identifies wood as the primary rural solid fuel. Coal (A) is also used but less commonly in villages due to cost and availability. Paraffin (C) is a liquid fuel, not solid. Coke (D) is a processed coal product, not naturally occurring, and is less commonly used in village settings.

Anthracite is a hard, compact variety of coal that has a sub-metallic lustre. It has the highest carbon content, the fewest impurities and the highest calorific content of all types of coal. The carbon content is between 92.1% - 98% . In lignite, the carbon content is 25-35%. Bituminous contains 60-80% carbon. In peat, the carbon content is less than 60%.

Coal gas, also known as town gas, was historically used primarily for illumination (lighting) in homes and street lamps before the widespread adoption of electricity. Option A correctly identifies this historical use. Disinfection (B) requires different gases. Deep freezing (C) uses refrigerants. Chemical preservation (D) is not a primary application of coal gas. The illuminating property of coal gas made it valuable for lighting applications.

Petroleum is a mixture of hydrocarbons.

Petroleum is separated into different parts by the process of fractional distillation.

Liquefied Petroleum Gas (LPG) is classified as a gaseous fuel that has been liquefied under pressure for storage and transportation. In its normal state at atmospheric pressure, LPG exists as a gas (propane and butane). Option C correctly identifies it as a gaseous fuel. Option A (solid fuel) is incorrect. Option B (liquid fuel) describes its storage form, not its fundamental classification. Option D is false as LPG is indeed a fuel.

Coal gas is produced by destructive distillation of coal and contains a mixture of gases. The primary components are hydrogen (H2), methane (CH4), and carbon monoxide (CO). Option A only lists two components, while option B correctly lists all three major constituents of coal gas.

The gas obtained during destructive distillation of coal is coal gas. 

Petroleum refining involves separating crude oil into its various components based on their boiling points. This separation technique is called fractional distillation. Carbonisation refers to converting coal to coke, while destructive distillation is used for coal gas production.