UPSC Prelims 2021 · GS Paper I
Question 17: Environment and Ecology
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.
AnswerUPSC’s answer is (b).
Copper smelting releases sulphur dioxide because copper ores are usually sulphides, so the roasting and smelting oxidise the sulphur into SO2, a major air pollutant that causes acid rain. The slag left behind can contain heavy metals such as arsenic and lead that can leach into soil and groundwater. Carbon monoxide is not the concern here: it is not released in lethal quantities by smelting. Remember: SO2 in the air and heavy metals from slag.
- 1. Carbon monoxide in lethal quantities is not what copper smelting is known for.
- 2. Slag can leach heavy metals into soil and water.
- 3. Smelting sulphide ores releases sulphur dioxide.
How you could have got this
- If you were sure statement 1 is not correct, (a), (c) and (d) go: each of them includes 1.
What you needed to know: Carbon monoxide in lethal quantities is not what copper smelting is known for.
Only (b) is left. You didn’t need statements 2 or 3.
Which options go is worked out from UPSC’s key and the options, not by a model.
Why each option is right or wrong
- (a) Wrong: statement 1 is not accepted as a concern.
- (b) Right: sulphur dioxide and leaching of heavy metals from slag are the concerns.
- (c) Wrong: it includes the carbon monoxide statement and drops the slag statement.
- (d) Wrong: statement 1 is not accepted.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2021, General Studies Paper I, Series A. The paper on upsc.gov.in.