Bitumen
Explanation
Crude oil (petroleum) is processed through fractional distillation to separate it into various useful fractions based on boiling points. Bitumen is the heavy, viscous residue left behind after the distillation of volatile components like petrol, diesel, and kerosene.
Option Analysis
- Bitumen (Correct): It is a black, sticky semi-solid form of petroleum. It is primarily used for the metalling (surfacing) of roads due to its excellent binding properties and water resistance. In modern road construction, bitumen has largely replaced coal tar.
- Paraffin wax (Incorrect): This is a white or colorless soft solid derivable from petroleum, coal, or oil shale. It is used in candles, ointments, wax paper, and polishes.
- Lubricating oil (Incorrect): This fraction is used to reduce friction, heat, and wear between mechanical components in engines and machinery.
- Diesel (Incorrect): This is a liquid fuel used in diesel engines for heavy vehicles (trucks, buses, trains) and electric generators.
Key Takeaway: Bitumen is the specific petroleum product used as a binder in road construction (metalling), whereas coal tar is a byproduct of coal processing.