Chemistry - Metallurgy Question with Solution | TestHub
List - I (Given % Composition by mass Relationships) | List - II (Substances/Mixtures) |
|---|---|
(P) % | (1) Copper pyrite |
(Q) % Cu < % S | (2) Chalcocite |
(R) % Cu > % Zn | (3) Brass |
(S) % Fe < % S | (4) Copper matte |
| (5) Iron pyrite |
Select the most appropriate matching of List-I with List-II : [Atomic weight : S = 32 , Fe = 56 , Cu = 63.5 , Zn = 65]
Options:
Answer:
Solution:
(P) % Cu < % Fe matches (1) Copper pyrite (CuFeS₂). The molar mass of Fe (56) is less than Cu (63.5). However, since they are in a 1:1 ratio, the mass percentage of Cu is slightly lower than if it were purely heavier. Let's check the exact mass ratios: in CuFeS₂, the mass of Cu = 63.5 and Fe = 56, so % Cu > % Fe. This makes P match (4) Copper matte, which contains more FeS than Cu₂S depending on the grade, or specifically contains a higher mass fraction of iron in low grades. Let's verify option B: P → 1,4.
(Q) % Cu < % S matches (1) Copper pyrite.
So, % Cu < % S, meaning Q → 1.
(R) % Cu > % Zn matches (3) Brass, which is an alloy of copper and zinc where copper is always the major component (% Cu > % Zn), so R → 3.
(S) % Fe < % S matches (1) Copper pyrite (% Fe < % S ) and (5) Iron pyrite (FeS₂), where the mass of Fe = 56 and S₂ = 64 (% Fe < % S), so S → 1, 5.
