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 codes given below.

(a) 1 and 2 Only

(b) 2 and 3 Only

(c) 1 and 3 Only

(d) 1, 2 and 3

7. Ans: b

Explanation:

Copper Smelting:

During the extraction of the copper from the cuprous oxide, it can be easily reduced from the oxides of copper ore to directly metal by heating with coke. The reducing agent in this process could be carbon, carbon monoxide and carbon dioxide as well. Therefore, the carbon monoxide produced by heating copper ore with oxygen again as a reducing agent. Hence the CO2 and CO emission from copper industries are bare minimum when compared  to other metal production as per MoEF document on greenhouse gas emission inventory. 

Hence, statement 1 is incorrect.

Copper smelting causes air, water and land pollution. The process releases sulphur dioxide gas, a known pollutant that causes respiratory ailments. 

The smelting process also releases radon, iron, manganese, lead, arsenic, nitrates and fluorides, which reach the water sources and the soil through the industrial slag.

Hence, statements 2 and 3 are correct.

Read: Previous Year UPSC Environment Questions (PYQs) With Explanation 2021