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 ✓ UPSC's answer
- (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
Why the answer is (a)
• Statement I says activated carbon is an effective and attractive tool for treating industrial effluents; the question is whether statements II and III are true and whether they explain why.
• Statement II is correct: activation creates a porous structure with a surface area of 500–1500 m² per gram, giving strong adsorption of heavy metals, dyes and organics — this directly explains its effectiveness (I).
• Statement III is correct: activated carbon can be made cheaply from carbon-rich wastes such as coconut shells, rice husk, sawdust and sludge — this explains why it is 'attractive', i.e. economical and sustainable (I).
• So both II and III are correct and each explains a part of statement I: II the efficacy, III the attractiveness.
• Hence option (a).
Why the other options are wrong
- (b) Both Statement II and Statement III are correct but only one of them explains Statement I
- Both II and III explain statement I, not just one of them.
- (c) Only one of the Statements II and III is correct and that explains Statement I
- Both II and III are correct, not just one.
- (d) Neither Statement II nor Statement III is correct
- Both II and III are correct.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2025, held on 25 May 2025. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.