chemistry : class12 Sulfide Ores of Sulfur : Occurrence of Group 16 elements : p-Block Elements MCQ Questions and Answers
Practice important
Sulfide Ores of Sulfur
MCQ questions and answers.
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MCQ Questions
1. Which sequence correctly matches the sulfide ore with its chemical formula?
A.
Iron pyrites—FeS; zinc blende—ZnS2; galena—PbS
B.
Iron pyrites—FeS2; zinc blende—ZnS; galena—PbS
C.
Iron pyrites—Fe2S3; zinc blende—ZnS; galena—PbS2
D.
Iron pyrites—FeS2; zinc blende—Zn2S; galena—Pb2S3
Correct Answer:
Iron pyrites—FeS2; zinc blende—ZnS; galena—PbS
Explanation:
Iron pyrites is FeS2, zinc blende is ZnS, and galena is PbS. These are important naturally occurring sulfide ores containing sulfur.
2. In iron pyrites, FeS2, the oxidation state of sulfur is best represented as:
A.
−2 for each sulfur atom, with no sulfur–sulfur interaction
B.
−1 for each sulfur atom, corresponding to an S–S unit
C.
0 for each sulfur atom because the compound is elemental sulfur
D.
+2 for each sulfur atom because iron is oxidized
Correct Answer:
−1 for each sulfur atom, corresponding to an S–S unit
Explanation:
FeS2 contains the disulfide ion, S2^2−. Therefore, each sulfur has oxidation state −1, unlike the isolated sulfide ion S^2− found in compounds such as ZnS and PbS.
3. Which set contains only sulfide ores of sulfur-bearing metals?
A.
Galena, zinc blende, cinnabar
B.
Gypsum, galena, zinc blende
C.
Calamine, iron pyrites, gypsum
D.
Baryte, cinnabar, iron pyrites
Correct Answer:
Galena, zinc blende, cinnabar
Explanation:
Galena (PbS), zinc blende (ZnS), and cinnabar (HgS) are all sulfide ores. Gypsum and baryte are sulfates, while calamine is not a sulfide ore.
4. A mineral sample contains a metal M combined with sulfur in the ratio M:S = 1:2, and sulfur occurs as a disulfide unit. Which commonly occurring sulfur ore fits this description?
A.
Galena
B.
Zinc blende
C.
Iron pyrites
D.
Cinnabar
Correct Answer:
Iron pyrites
Explanation:
Iron pyrites has the formula FeS2 and contains the disulfide unit S2^2−. Galena, zinc blende, and cinnabar have formulas PbS, ZnS, and HgS respectively.
5. Which pair of sulfide ores contains sulfur in the oxidation state −2, rather than in a disulfide unit?
A.
Iron pyrites and copper pyrites
B.
Zinc blende and galena
C.
Iron pyrites and galena
D.
Copper pyrites and iron pyrites
Correct Answer:
Zinc blende and galena
Explanation:
Zinc blende is ZnS and galena is PbS; both contain isolated sulfide ions, S^2−, so sulfur has oxidation state −2. Iron pyrites contains S2^2−.
6. Copper pyrites, an important sulfide ore, is correctly represented by which formula and constituent metals?
A.
CuS, containing copper and sulfur only
B.
Cu2S, containing copper and sulfur only
C.
CuFeS2, containing copper, iron, and sulfur
D.
CuFe2S3, containing copper, iron, and sulfur
Correct Answer:
CuFeS2, containing copper, iron, and sulfur
Explanation:
Copper pyrites, also called chalcopyrite, has the formula CuFeS2. It is a mixed sulfide ore containing copper, iron, and sulfur.
7. Which sulfide ore is correctly paired with the metal whose extraction it primarily represents?
A.
Cinnabar—mercury
B.
Galena—zinc
C.
Zinc blende—lead
D.
Iron pyrites—copper
Correct Answer:
Cinnabar—mercury
Explanation:
Cinnabar is HgS, the principal sulfide ore of mercury. Galena is PbS, zinc blende is ZnS, and iron pyrites is FeS2.
8. Among FeS2, ZnS, PbS, and HgS, which compound is distinguished by sulfur atoms being bonded to each other within the anion?
A.
ZnS
B.
PbS
C.
HgS
D.
FeS2
Correct Answer:
FeS2
Explanation:
FeS2 contains the disulfide ion S2^2−, in which the two sulfur atoms are bonded. ZnS, PbS, and HgS contain separate sulfide ions rather than S–S bonded units.
9. A student lists the formulas FeS2, CuFeS2, ZnS, and HgS as sulfide ores. Which ore in this list contains two different metals?
A.
Iron pyrites
B.
Copper pyrites
C.
Zinc blende
D.
Cinnabar
Correct Answer:
Copper pyrites
Explanation:
Copper pyrites has the formula CuFeS2 and contains the two metals copper and iron. Iron pyrites, zinc blende, and cinnabar contain only one metallic element each.
10. Which statement correctly distinguishes iron pyrites from zinc blende on the basis of their sulfide species?
A.
Iron pyrites contains S2^2−, whereas zinc blende contains S^2−
B.
Iron pyrites contains S^2−, whereas zinc blende contains S2^2−
C.
Both contain S2^2−, but only zinc blende contains a metal
D.
Both contain S^2−, but iron pyrites has two sulfur atoms per formula unit