Co2
Introduction
Carbon Dioxide (CO₂) is a colorless, odorless gas found naturally in Earth’s atmosphere.
It plays a crucial role in photosynthesis, respiration, and climate regulation, but excess CO₂ is a major cause of global warming.
In Bihar, CO₂ levels are affected by vehicle emissions, stubble burning, and use of biogas and composting systems.
Basic Properties of CO₂
- Molecular Formula: CO₂
- Composed of 1 carbon atom and 2 oxygen atoms
- Soluble in water → forms carbonic acid (H₂CO₃)
- Heavier than air, does not support combustion
- Non-flammable but a major greenhouse gas
📝 PYQ (BPSC): What is the chemical formula of carbon dioxide? → CO₂
📝 Expected MCQ: Does CO₂ support combustion? → No
Natural Sources of CO₂
- Respiration by humans and animals
- Decomposition of organic matter
- Volcanic eruptions
- Ocean release of dissolved CO₂
- Forest fires
Man-made (Anthropogenic) Sources
- Burning of fossil fuels: coal, petrol, diesel
- Vehicle emissions
- Industrial activities
- Deforestation (reduces CO₂ absorption)
- Cement production
📝 Expected MCQ: Which activity adds the most CO₂ to the atmosphere? → Burning fossil fuels
Environmental Role of CO₂
🌿 In Nature
- Used by plants during photosynthesis → converts CO₂ into oxygen and glucose
- Maintains Earth's carbon cycle balance
- Essential for plant growth
☀️ In Climate
- Acts as a greenhouse gas → traps heat in atmosphere
- Contributes to global warming and climate change
- Measured in parts per million (ppm) in air
📝 PYQ: CO₂ is used by plants in? → Photosynthesis
📝 Expected MCQ: Which gas is responsible for global warming? → Carbon dioxide
CO₂ and Acid Rain
- CO₂ + H₂O → H₂CO₃ (Carbonic acid)
- Acidifies rainwater and water bodies
- Can damage soil and aquatic ecosystems
CO₂ in Daily Life
- Used in aerated drinks
- Used in fire extinguishers (Class B and C fires)
- Used in refrigeration systems
- Dry ice is solid CO₂ → used for cooling perishable goods
📝 Expected MCQ: What is dry ice? → Solid CO₂
Bihar-Specific Relevance
🚜 Agriculture & Biomass
- Biogas plants release CO₂ and CH₄ during decomposition
- Use of organic compost reduces net CO₂ emissions
- Crop residue burning in districts like Samastipur increases CO₂
🌆 Urban Pollution
- Vehicular and construction emissions increase CO₂ in cities like Patna, Muzaffarpur, Gaya
- CO₂ is a major contributor to poor AQI (Air Quality Index)
🌳 Plantation Drives
- Bihar’s Hariyali Mission promotes tree plantation to absorb CO₂ naturally
📝 Expected MCQ: Which initiative in Bihar helps reduce CO₂? → Jal Jeevan Hariyali Mission
Health & Climate Effects of CO₂
- Not toxic in small amounts, but high levels can cause:
- Headaches
- Fatigue
- Reduced concentration
- Global effects:
- Ice melt, sea-level rise
- Extreme weather
- Crop yield changes
PYQs + Expected MCQs
📝 PYQ (BPSC): Which gas is essential for photosynthesis? → CO₂
📝 PYQ (CDPO): Which gas causes global warming? → Carbon dioxide
📝 Expected MCQ: Which gas is used in soda water? → CO₂
📝 Expected MCQ: What is the solid form of CO₂ called? → Dry ice
📝 Expected MCQ: Bihar's crop burning releases which gas? → CO₂
📝 Expected MCQ: CO₂ reacts with water to form? → Carbonic acid
Quick Revision Points
- CO₂ = 1 Carbon + 2 Oxygen → Non-flammable gas
- Released via respiration, combustion, decay
- Used in: photosynthesis, soda, extinguishers, dry ice
- Causes global warming, forms carbonic acid
- Bihar: CO₂ from vehicles, biomass burning; controlled via plantation and biogas
Sources Used
- NCERT Science Class 9–10 – Carbon and Its Compounds
- Lucent GK – Chemistry Section
- Drishti Science Quick Book
- EduTeria + Ghatna Chakra PYQs (BPSC, CDPO)
- BSPCB Reports – Bihar Pollution & AQI Data
- Jal Jeevan Hariyali Campaign – Bihar Govt
- IPCC Climate Change Summary – India Focus