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?

1. A

   Both statement II and Statement III are correct and both of them explain Statement I

   Both Statement II and Statement III are correct and both explain Statement I. Activated carbon has a very large surface area and adsorbs heavy metals (II) - that is why it pulls pollutants from effluent. It can be made from high-carbon wastes such as coconut shell or rachis (III) - that is why it is a cheap, attractive tool. I follows from both.

2. B

   Both Statement II and Statement III are correct but only one of them explains Statement I

   Both II and III are correct but only one explains I. Both do: adsorption chemistry and cheap feedstock are two reasons it is used.

3. C

   Only one of the Statements II and III is correct and that explains Statement I

   Only one of II and III is correct and that explains I. Both II and III hold.

4. D

   Neither Statement II nor Statement III is correct.

   Neither II nor III is correct. Both hold, and both support I.

Summary. Official key is (a): both II and III are correct and both explain I. Activated carbon’s huge surface adsorbs metals, and it can be made from high-carbon wastes — that is why it is used on effluent.