Q.Which of the following metals is generally found in free state?
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🔒 Start your 14-day free trial to unlock the full solution →Concept understanding — Occurrence of Metals (Ores and Minerals)
A mineral is a naturally occurring substance in the earth's crust with a definite chemical composition. A mineral from which a metal can be extracted profitably and conveniently is called an ore — so every ore is a mineral, but not every mineral is an ore (e.g., clay contains aluminium but bauxite, not clay, is aluminium's ore). Metals occur in nature either in the:
- Native (free) state — unreactive metals like Au, Ag, Pt, Cu, which resist corrosion. …
A metal occurs in its free (native) state in nature only if it is chemically unreactive enough to resist oxidation by air, water and acids over geological time. …
Metals low in the reactivity series occur free (native). Of the options, only gold (Au) is noble enough, so it is found in the free state.
A metal is found in the free (native) state only if it is chemically unreactive — it must resist reaction with air, water and acids over geological time. Reactive metals are always found combined as oxides, sulphides, carbonates, etc.
- Cu, Al and Fe are all reactive enough to occur as compounds (ores): Cu as copper pyrites/copper glance, Al as bauxite, Fe as haematite/magnetite. …
Showing the 12 most recent of 14 on this concept.
- CBSE 2024Set D1 markMCQQ.Which of the following metals is generally found in free state?(a) Cu(b) Au(c) Al(d) Fe
›Reveal solutionSolution
Metals low in the reactivity series occur free (native). Of the options, only gold (Au) is noble enough, so it is found in the free state.
A metal is found in the free (native) state only if it is chemically unreactive — it must resist reaction with air, water and acids over geological time. Reactive metals are always found combined as oxides, sulphides, carbonates, etc.
- Cu, Al and Fe are all reactive enough to occur as compounds (ores): Cu as copper pyrites/copper glance, Al as bauxite, Fe as haematite/magnetite. …
- CBSE 2024Set D1 markMCQQ.Which of the following statements is true?(a) All ores are minerals(b) All minerals are ores(c) A mineral cannot be an ore(d) An ore cannot be a mineral
›Reveal solutionSolution
A mineral is any naturally occurring compound of a metal; an ore is a mineral from which the metal can be extracted conveniently and economically. So every ore is a mineral, but not every mineral is an ore.
Definitions:
- Mineral: a naturally occurring inorganic substance containing a metal in combined (or sometimes free) form.
- Ore: a mineral from which the metal can be extracted economically and conveniently. …
- CBSE 2024Set D1 markMCQQ.An ore having two different metal atoms is(a) Haematite(b) Galena(c) Magnetite(d) Copper pyrite
›Reveal solutionSolution
Copper pyrite is CuFeS2, containing both Cu and Fe — two different metal atoms. The others contain only one metal.
Check each formula:
- Haematite = Fe2O3 (only Fe)
- Galena = PbS (only Pb)
- Magnetite = Fe3O4 (only Fe) …
- CBSE 2023Set F1 markMCQQ.The important oxide ore of iron is(a) Siderite(b) Haematite(c) Pyrite(d) Bauxite
›Reveal solutionSolution
The oxide ore of iron is haematite, Fe2O3 — option (B).
Classifying the given ores:
- Siderite = FeCO3 → a carbonate ore of iron.
- Haematite = Fe2O3 → an OXIDE ore of iron (the most important one).
- Pyrite = FeS2 → a sulphide ore of iron.
- Bauxite = Al2O3·2H2O → an oxide ore of aluminium, not iron. …
- CBSE 2023Set F1 markMCQQ.Pyrolusite is an ore of which of the following?(a) Magnesium(b) Manganese(c) Zinc(d) Iron
›Reveal solutionSolution
Pyrolusite (MnO2) is an ore of manganese — option (B).
Pyrolusite is the mineral form of manganese dioxide, MnO2, and is the chief ore used for the extraction of manganese. It is not an ore of magnesium, zi …
- CBSE 2023Set ANNUAL1 markMCQQ.Calamine is ore of -(a) Al(b) Fe(c) Cu(d) Zn
›Reveal solutionSolution
Calamine is one of the principal carbonate ores of zinc.
Zinc occurs in nature mainly as: Zinc blende / Sphalerite (ZnS, sulphide ore), Calamine / Smithsonite (ZnCO3, carbonate ore), and Zincite (ZnO, oxide ore). Calamine (ZnCO3) is roa …
- CBSE 2022Set E1 markMCQQ.The most abundant metal in earth crust is(a) Al(b) Fe(c) Ca(d) Na
›Reveal solutionSolution
Aluminium is the most abundant metal (and the third most abundant element overall) in the earth's crust.
By mass, the most abundant elements in the earth's crust are oxygen and silicon (both non-metals/metalloids), followed by aluminium. Thus among METALS, aluminium is the most abundant (~8% of the crust), ahead of iron (the second …
- CBSE 2021Set A1 markMCQQ.The formula of copper pyrite is(a) CuFeS(b) CuFeS2(c) Cu2S(d) Cu2FeS2
›Reveal solutionSolution
Copper pyrite = chalcopyrite = CuFeS2, the chief ore of copper.
Copper pyrite, also called chalcopyrite, is the most important ore of copper. It is a mixed (double) sulphide of copper and iron with the formula CuFeS2. Distinguishing it from the distractors:
- CuFeS: incorrect stoichiometry. …
- CBSE 2021Set A1 markMCQQ.The metal always found in free state is(a) Gold(b) Silver(c) Copper(d) Sodium
›Reveal solutionSolution
Metals occur free only if they are very unreactive; among the choices, gold is the noble metal, so it is found free in nature.
A metal is found in the free (native) state only when it is chemically unreactive, i.e. it resists oxidation by air, water and acids.
- Sodium (D) is an extremely reactive alkali metal that reacts violently with water and air, so it is never found free — always as compounds (NaCl, etc.). …
- CBSE 2021Set A1 markMCQQ.Galena is an ore of(a) Sn(b) Pb(c) Si(d) Ag
›Reveal solutionSolution
Galena = PbS = the main ore of lead.
Galena is the naturally occurring mineral lead(II) sulphide, PbS. It is the most important ore from which lead metal is extracted (by roasting to PbO, then reduction).
- (A) Tin (Sn) main ore is cassiterite (SnO2). …
- CBSE 2021Set TERM11 markMCQQ.Which one of the following is most abundant in earth's crust ?(a) Mg(b) Na(c) Al(d) Fe
›Reveal solutionSolution
Among Mg, Na, Al and Fe, aluminium is the most abundant in the earth's crust.
By mass, the earth's crust is dominated by oxygen and silicon, and among metals, aluminium is the most abundant (about 8.3% by mass of the crust), followed by iron (~5%), calcium, sodium, potassium and magnesium in smaller amou …
- CBSE 2020Set HE8221 markMCQQ.Bauxite is the ore of -(a) Al(b) Cu(c) Fe(d) Zn
›Reveal solutionSolution
Bauxite, Al₂O₃·2H₂O, is the chief ore from which aluminium metal is extracted (via the Bayer process, then the Hall–Héroult electrolysis).
Ores are naturally occurring minerals from which a metal can be profitably extracted.
- Bauxite (hydrated aluminium oxide, Al2O3⋅2H2O) is the principal ore of aluminium. It is purified by the Bayer process (digestion in hot NaOH) to give pure Al2O3, which is then electrolysed by the Hall–Héroult process to give metallic aluminium. …
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