Chapter 12: What If It Finishes?
खत्म हो जाए तो...? (पेट्रोलियम, रिफाइनरी एवं अदालज की बावड़ी)
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.
- Petroleum (कच्चा तेल) formation: Formed naturally deep under the seabed and earth over millions of years from decomposing prehistoric marine organisms.
- Crude oil properties: Thick, dark, smelly, and greasy unrefined liquid; not directly usable in vehicles.
- Refineries (तेल शोधनशाला): Crude oil is sent to petroleum refineries where fractional distillation separates it into Petrol, Diesel, Kerosene, LPG (cooking gas), Wax, Coal tar, and Aviation fuel.
- Adalaj Stepwell (अदालज की बावड़ी): Located approximately 18 kilometers from Ahmedabad, Gujarat; famous five-story underground architectural stepwell.
- Exhaustible resource: Petroleum takes millions of years to form naturally, but human machines are extracting it in decades. It will eventually finish if not conserved.
- CNG (Compressed Natural Gas): Clean automobile alternative that produces far less smoke, carbon monoxide, and toxic particulate matter than diesel.
- Trap: CBSE claims crude petroleum is a clean, thin, pleasant-smelling liquid. Correct: Crude petroleum is thick, dark, greasy, and smelly (बदबूदार).
- Trap: CBSE claims Adalaj stepwell is located in Rajasthan. Correct: Adalaj stepwell is 18 km from Ahmedabad, Gujarat.
NCERT Core Facts: Petroleum Formation, Refineries & Conservation
Chapter 12 follows schoolchildren travelling on a highway bus from Ahmedabad towards the historic Adalaj stepwell (18 km away), observing traffic jams, vehicle exhaust smoke, and petrol pump meters.
1. What is Crude Petroleum (कच्चा तेल)?
- Natural Origin: Petroleum was formed millions of years ago deep inside the Earth and ocean beds from the remains of microscopic sea plants and creatures.
- Physical Characteristics (Direct CTET MCQ Question):
- It is a smelly, thick, dark-coloured, oily liquid (बदबूदार, गाढ़ा, गहरे रंग का तेल).
- It contains a complex mixture of hundreds of hydrocarbons, dirt, and chemicals.
2. Petroleum Refineries & Fractional Distillation
- Crude oil extracted from oil wells cannot be poured directly into scooter or car tanks.
- It is transported via pipelines to Refineries (तेल शोधनशाला), where it is heated and distilled into distinct commercial fuels and by-products:
- a.Petrol (Car and motorcycle fuel)
- b.Diesel (Heavy trucks, buses, tractors, and agricultural pump sets)
- c.Kerosene (मिट्टी का तेल) and LPG (Domestic cooking gas)
- d.Aviation Turbine Fuel (Airplane fuel)
- e.Wax (मोम), Coal Tar (डामर for roads), and Lubricating Engine Grease
- f.Plastics and Synthetic Paints are also manufactured from petroleum derivatives!
3. The Chulha & Wood Smoke Tragedy in Rural India
- In many rural households, women spend hours collecting dry wood, cow dung cakes (उपले), and dry leaves to burn in mud chulhas.
- The dense indoor smoke causes severe chronic coughing, respiratory illness, and lung damage.
- Switching to LPG cylinders or solar energy protects women's health and eliminates forest degradation.
Test Your Mastery: What If It Finishes?
Authentic CBSE exam questions tested directly from this NCERT chapter.
Select the correct characteristics of crude petroleum from the following:
कच्चे पेट्रोलियम के सही अभिलक्षणों को चुनिए:
Which of the following is NOT obtained from petroleum?
निम्नलिखित में से कौन सा पेट्रोलियम से प्राप्त नहीं होता है?
What are the physical characteristics of crude petroleum according to NCERT?
According to NCERT Class 5 EVS Chapter 12, crude petroleum is a smelly, thick, dark-colored, greasy liquid found deep beneath the Earth's surface.
Which fuels and products are obtained from refining petroleum?
Petroleum refining yields Petrol, Diesel, Kerosene, LPG, Aviation fuel, Wax, Coal tar (for roads), engine grease, and raw chemical feedstocks for plastics and paints.