Question

Which one of the following reactions does not occur during extraction of copper?

• A. $CaO + SiO _2 \rightarrow CaSiO _3$
• B. $2 Cu _2 S +3 O _2 \rightarrow 2 Cu _2 O +2 SO _2$
• C. $FeO + SiO _2 \rightarrow FeSiO _3$
• D. $2 FeS +3 O _2 \rightarrow 2 FeO +2 SO _2$

Answer 1

The Correct Option is A

To answer the question of which reaction does not occur during the extraction of copper, we need to understand the extraction process of copper from its ores, typically sulfide ores like chalcopyrite (CuFeS₂).

Let's analyze each option:

1. \(CaO + SiO_2 \rightarrow CaSiO_3\): This reaction involves the combination of calcium oxide (lime) and silica to form calcium silicate. This is not a part of the copper extraction process. It is typically a part of the iron extraction process where it acts as a slag-forming reaction to remove impurities. Therefore, this reaction is not involved in the extraction of copper.
2. \(2 Cu_2S + 3 O_2 \rightarrow 2 Cu_2O + 2 SO_2\): This reaction represents the roasting of copper(I) sulfide, where air (oxygen) is used to convert sulfide ores into oxides, while sulfur dioxide is released. This is a common step in copper extraction.
3. \(FeO + SiO_2 \rightarrow FeSiO_3\): This reaction shows the formation of iron silicate from iron oxide and silica, which is again related to slag formation in iron extraction processes, not copper extraction.
4. \(2 FeS + 3 O_2 \rightarrow 2 FeO + 2 SO_2\): This is a reaction involving iron sulfide being oxidized to iron oxide, producing sulfur dioxide. This is not specific to copper extraction, although iron sulfide impurities in copper ores might undergo a similar reaction during roasting.

From the above analysis, the reaction \(CaO + SiO_2 \rightarrow CaSiO_3\) is unrelated to copper extraction. It is primarily associated with the steel industry where it's used to form slag for removing impurities from iron.

Therefore, the reaction that does not occur during copper extraction is the first option:

Correct Answer: \(CaO + SiO_2 \rightarrow CaSiO_3\).