Why is there a concern about copper smelting plants? 1. They may release lethal quantities of carbon monoxide into environment. 2. The copper slag can cause the leaching of some heavy metals into environment. 3. They may release sulphur dioxide as a pollutant. Select the correct answer using the code given below.

Answer: B. Statements 2 and 3 are correct; Statement 1 is wrong. COPPER SMELTING involves extracting copper from sulphide ores (chalcopyrite, chalcocite). The process generates significant environmental pollutants. Statement 1 is WRONG. Copper smelting does NOT release 'lethal quantities of CARBON MONOXIDE' as its characteristic concern. While any combustion-based industrial process generates some CO, the principal gaseous emission from copper smelting is SULPHUR DIOXIDE (from the roasting of copper sulphide ores). CO is not what makes copper smelting environmentally controversial. Statement 2 is CORRECT. COPPER SLAG (the waste residue after extracting copper from molten metal) CAN LEACH HEAVY METALS into the environment. Slag contains residual copper, lead, arsenic, cadmium, zinc, and nickel that can leach into groundwater if dumped without proper engineered containment. Several Indian copper smelters (e.g., Sterlite Tuticorin) faced regulatory and judicial scrutiny over slag-pile leaching. Statement 3 is CORRECT. Copper smelting RELEASES SUBSTANTIAL SULPHUR DIOXIDE (SO2). The conversion of copper sulphide ores produces SO2 as a primary by-product: 2Cu2S + 3O2 → 2Cu2O + 2SO2 SO2 contributes to acid rain and respiratory health damage. Modern plants must capture SO2 (typically to manufacture sulphuric acid as a co-product) to meet environmental norms. The 2018 closure of Sterlite Tuticorin was triggered by community protests over SO2 emissions. Source: CPCB / MoEFCC emission norms for non-ferrous metallurgy / Madras HC and SC orders on Sterlite.