Coal tar is obtained from the processing of coal. It can easily take up variety of colours. It is a thick viscous substance and thus, is useful for making paints, dyes, etc. 

Natural gas accumulates above the surface of petroleum oil during its formation. Methane is formed in a natural way or obtained during the formation of petroleum oil. Biogas is produced by biological breakdown of organic matter in the absence of oxygen. Coal gas is obtained as a by-product during the processing of coal so as to obtain coke. 

Coal is heated properly in the absence of air at a high temperature of about 1000^oC.

The process of heating coal in the absence of air does not lead to the burning of coal, but forms many by-products. This process is called destructive distillation of coal. The main by-products of destructive distillation are: coke, coal tar, amino acid liquor and coal gas.

Petroleum is used in the manufacture of detergents, fibres (polyester, nylon, acrylic, etc.), polythene and other man-made plastics. Due to its great commercial importance, petroleum is also called ‘black gold’.

Coke is used as a fuel and a reducing agent in smelting of iron ore in a blast furnace. In this process, iron oxide (haematite) is reduced to collect iron.

Decomposition (or rotting) is the process by which organic substances are broken down into simpler forms of matter and produces a gas called methane.

Gross Calorific Value (GCV (kJ/kg)) Anthracite: 32500 - 34000 Lignite: 16300 Bituminous coal: 17000 - 23250 Peat: 13800 - 20500

Petroleum refining process forms paraffin wax, which is a product made from the constituents of petroleum and is used for making candles.

Fertiliser manufacturing industries use ammoniacal liquor, which is a by-product of coal tar, which in turn is obtained during the destructive distillation of coal. All other products are manufactured with the use of petroleum constituents.

Automobiles do not use coal as fuel.

Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams.

Coal is formed by slow conversion of dead plants into carbon under geothermal conditions of high pressure and high temperature.

Coal tar has an unpleasant smell.

Haematite is an iron ore, not a stage during formation of coal.