JEE Main 2023 · 1 February · evening · Numerical answer · +4 / −0
Among following compounds, the number of those present in copper matte is ___________.
A. CuCO₃
B. Cu₂S
C. Cu₂O
D. FeO
Answer and solution
Answer 1
Solution
Chemistry ma’am · 3 steps
Copper matte is just two sulphides, Cu₂S and FeS. Check each compound against that pair.
- What matte is. Copper pyrites is roasted and then smelted with silica in a reverberatory furnace. The molten layer of sulphides that collects at the bottom is copper matte, a mixture of Cu₂S and FeS.
- Where oxides go. Iron oxide is removed as slag: FeO + SiO₂ → FeSiO₃. Any Cu₂O formed is turned back into sulphide by Cu₂O + FeS → Cu₂S + FeO. So neither oxide stays in the matte.
Compound Role in extraction In matte? A. CuCO₃ a carbonate ore (as in malachite), not formed from pyrites No B. Cu₂S main component of matte Yes C. Cu₂O reacts with FeS and becomes Cu₂S No D. FeO removed as slag FeSiO₃ No - So. Only Cu₂S is present in copper matte, so the number is 1.
The common slip: 2. Counting FeO as well gives 2. Iron is in the matte only as FeS, and FeO leaves as FeSiO₃ slag.
The idea to keep. Matte holds only sulphides, Cu₂S and FeS. Oxides either go into slag as silicates or are converted back to Cu₂S.
Answer from the NTA final answer key. Solution by PrepWiser.