Chapter 5: Coal and Petroleum
कोयला और पेट्रोलियम (कार्बोनीकरण, कोक, कोलतार, पेट्रोलियम प्रभाजन एवं बिटुमेन)
Don't Let a 20-Minute Bubbling Delay Cost You CTET Qualification
In offline CTET exams, bubbling 150 bubbles takes 18 to 22 minutes of mechanical time. A single misaligned row can trigger an 8-question domino error. Practice bubble-filling this chapter's solved MCQs inside Mentora's official OMR simulator.
- Natural Resources: Inexhaustible (Sunlight, Air) vs Exhaustible (Fossil fuels: Coal, Petroleum, Natural Gas, Minerals, Forests).
- Formation of Coal: Formed about 300 million years ago when dense swamp forests were buried under subterranean earth under high temperature and pressure. The slow biochemical conversion of dead vegetative matter into coal is termed Carbonisation (कार्बोनीकरण).
- By-products of Coal Processing (Destructive Distillation):
- - Coke (कोक): Tough, porous, black substance; almost pure elemental carbon. Used in the manufacture of steel and extraction of metals.
- - Coal Tar (कोलतार): Thick black liquid with unpleasant smell; mixture of ~200 chemical substances. Used for synthetic dyes, drugs, perfumes, explosives, paints, and Naphthalene balls (used to repel moths).
- - Coal Gas: Byproduct during coke manufacture; historical lighting fuel, now used as industrial heating fuel.
- Petroleum Refining & Fractional Distillation Fractions:
- - Petroleum Gas (LPG): Liquefied for home and industrial fuel.
- - Petrol (Gasoline): Motor fuel, aviation spirit, dry cleaning solvent.
- - Kerosene: Fuel for household stoves, pressure lamps, and jet aircraft engine fuel.
- - Diesel: Heavy motor vehicles (trucks, tractors, buses, generators).
- - Lubricating Oil: Machine lubrication.
- - Paraffin Wax: Ointments, candles, vaseline.
- - Bitumen (बिटुमेन): Used for paints and road surfacing (Has largely replaced coal tar in modern highway metalling!).
- Compressed Natural Gas (CNG): Stored under high pressure; clean non-polluting fuel because it leaves no residue; distributed via pipeline networks (e.g. Vadodara, Delhi).
- Trap: What petroleum fraction has replaced coal tar for metalling road surfaces today? Correct: BITUMEN (बिटुमेन).
- Trap: Naphthalene balls used to repel moths and insects are obtained from: Correct: COAL TAR (कोलतार), not petroleum wax.
- Trap: Coke is an impure form of carbon. FALSE: Coke is ALMOST PURE form of carbon (98%+ pure).
NCERT Core Facts: Carbonisation & Petrochemical Fractions
Refining fractions and coal derivatives are frequently examined in CTET Paper 2:
1. Products of Destructive Distillation of Coal
┌──> [Coke (कोक)] ─────── Almost pure carbon; steel extraction
[Bituminous Coal] ──┼──> [Coal Tar (कोलतार)] ── Mixture of ~200 compounds; naphthalene balls
└──> [Coal Gas] ──────── Industrial heating fuel2. Petroleum Distillation Fractions & Applications
| Petroleum Fraction | Primary Industrial / Domestic Utility | CTET Exam Trap |
|---|---|---|
| LPG | Domestic kitchen cylinder fuel | Odorized with ethyl mercaptan for leak detection |
| Petrol | Light vehicles, dry cleaning solvent | Highly volatile |
| Kerosene | Wicks, pressure stoves, jet aircraft | Specially refined for aviation turbines |
| Diesel | Heavy transport trucks, electric generators | Higher boiling fraction than petrol |
| Paraffin Wax | Vaseline, cosmetic creams, candles | Saturated hydrocarbon wax |
| Bitumen (बिटुमेन) | Road metalling and anti-corrosive paints | Replaced coal tar for modern roads |
Test Your Mastery: Coal and Petroleum
Authentic CBSE exam questions tested directly from this NCERT chapter.
Which petroleum product has nowadays largely replaced coal tar for the purpose of surfacing and metalling road highways?
सड़कों की सतह पर पक्की परत बिछाने के लिए आजकल कोलतार के स्थान पर किस पेट्रोलियम उत्पाद का बड़े पैमाने पर उपयोग किया जाता है?
Naphthalene balls used to protect stored woolen clothes against moths and insect pests are derived from which fraction?
ऊनी कपड़ों को कीड़ों और पतंगों से बचाने के लिए इस्तेमाल की जाने वाली नेफ़थलीन की गोलियाँ किस अंश से प्राप्त की जाती हैं?
What is carbonisation in the context of fossil fuels?
The slow geological process of biochemical transformation of buried dead vegetation into coal under extreme heat and pressure over millions of years.
Which petroleum product is nowadays used in place of coal-tar for surfacing roads?
Bitumen (बिटुमेन), a heavy, viscous petroleum distillation residue.