📘 IAS Prelims 2025 — GS-I Q.50 | Classroom Explanation

(Environment & Ecology | Pollution Control)

📌 Question

Q.50) Consider the following statements:

Statement I:
Activated carbon is a good and an attractive tool to remove pollutants from effluent streams and to remediate contaminants from various industries.

Statement II:
Activated carbon exhibits a large surface area and a strong potential for adsorbing heavy metals.

Statement III:
Activated carbon can be easily synthesized from environmental wastes with high carbon content.

Which one of the following is correct in respect of the above statements?

(a) Both Statement II and Statement III are correct and both of them explain Statement I
(b) Both Statement II and Statement III are correct but only one of them explains Statement I
(c) Only one of the Statements II and III is correct and that explains Statement I
(d) Neither Statement II nor Statement III is correct

✅ Correct Answer: (a)

🧑‍🏫 Classroom Explanation

This question integrates material science with environmental remediation, a rising UPSC theme linking waste-to-wealth and pollution control technologies.

🔍 Statement-wise Analysis

✅ Statement I: Correct

• Activated carbon is widely used in:

• Wastewater treatment
• Industrial effluent purification
• Air and water filtration

• It removes:

• Organic pollutants
• Heavy metals
• Dyes
• Toxic chemicals

➡️ Hence, it is an effective and attractive remediation tool.

✅ Statement II: Correct and explains Statement I

• Activated carbon has:

• Extremely large surface area
• Microporous structure
• High adsorption capacity

• These properties enable:

• Strong binding of heavy metals (lead, mercury, cadmium)
• Adsorption of organic contaminants

➡️ This directly explains its effectiveness in pollutant removal.

✅ Statement III: Correct and explains Statement I

• Activated carbon can be synthesized from high-carbon waste materials such as:

• Coconut shells
• Wood
• Agricultural residues
• Coal-based wastes

• Preparation methods:

• Physical activation
• Chemical activation

• This makes it:

• Cost-effective
• Sustainable
• Suitable for decentralized applications

➡️ Ease of synthesis explains why it is an attractive remediation option.

🧮 UPSC-Style Logical Linking

➡️ Both II and III explain I

🎯 Final Answer

✅ Correct Answer: (a)

📦 High-Value Prelims Add-Ons (Info Box)

🧠 One-Line Memory Hook

Huge surface + waste-derived = activated carbon’s pollution power.

♻️ Waste-to-Wealth Link

• Aligns with:

• Circular economy
• Sustainable waste management
• Low-cost water purification

⚠️ UPSC Trap Alert

• Don’t confuse:

• Adsorption (surface binding)
• Absorption (bulk uptake)