Chemistry - Metallurgy Question with Solution | TestHub
In both calcination and roasting, an ore is converted into its oxide, albeit through different chemical pathways. Calcination is the process in which the ore is heated below its melting point, either in the absence or in a limited supply of air, with the aim of driving off volatile impurities, moisture, water of hydration, and organic matter from the ore. Carbonate, bicarbonate, and hydroxide ores are generally subjected to calcination, which produces the metal oxide after expelling CO₂ or H₂O in the process.
In the process of roasting, concentrated ore is heated strongly, below its melting point, in the presence of air with or without some other additives, in order to bring about desired changes. Generally, sulfide ores are subjected to roasting, where oxides are formed and SO₂ is expelled.
Ore of a metal Roasted ore Metal
(X)
Ore of same metal Calcinated ore Metal
(Y)
Select CORRECT option :
Options:
Answer:
Solution:
Chalcocite (Cu₂S) is a sulphide ore → undergoes roasting → Cu₂O → Cu, so (A) is correct for roasting route.
Galena (PbS) on roasting gives PbO → Pb → PbCO₃ (cerussite as intermediate ore family linkage), so (B) fits the reduction pathway idea.
Zinc blende (ZnS) on roasting gives ZnO and reduction leads to calamine (ZnCO₃·Zn(OH)₂ type association), so (C) is also consistent.
Hence both (A) and (B) satisfy the given transformation pattern.