coal tar is a black thick liquid with unpleasant smell and coal gas is obtained during the processing of coal to get coke

Coal Tar and Coal Gas
Coal tar and coal gas are two byproducts of coal processing that have various industrial applications. Here is a detailed explanation of each:

Coal Tar:
- Coal tar is a dark, viscous liquid obtained during the destructive distillation of coal.
- It is a complex mixture of organic compounds, including polycyclic aromatic hydrocarbons (PAHs), phenols, and heterocyclic compounds.
- Coal tar has been used for centuries in various applications such as roofing, road construction, and as a preservative in wood products.
- It is also a key ingredient in the production of chemicals like creosote, naphthalene, and benzene.
- Coal tar is known for its waterproofing and antiseptic properties, making it valuable in the manufacturing of cosmetics, pharmaceuticals, and dyes.

Coal Gas:
- Coal gas, also known as town gas, is a mixture of gases produced by the distillation of coal.
- The main components of coal gas are hydrogen, methane, carbon monoxide, and carbon dioxide.
- Historically, coal gas was used for lighting and heating in households before the widespread use of natural gas.
- It was also used as a fuel for industrial processes and transportation.
- The production of coal gas has declined with the advent of cleaner energy sources, but it is still used in certain niche applications.
In conclusion, coal tar and coal gas are important byproducts of coal processing with diverse industrial uses. While coal tar is valued for its chemical properties in various applications, coal gas has been historically significant for its role in lighting, heating, and fuel production.