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MHT-CET Chemistry · Transition and Inner Transition Elements

Alloys, Ores and Catalysts of the Transition Metals

Transition metals mix readily into alloys because their atoms are similar in size, occur in nature as oxide, carbonate and sulphide ores, and act as catalysts because they can change oxidation state and adsorb reactants on their surfaces.

All Transition and Inner Transition Elements notesMHT-CET Chemistry strategy

Why this matters

11 PYQs, none HARD. Of the seven set from 2021 to 2025, two name the alloy for a use (nichrome for gas turbine engines, stainless steel for the fuselage of ultra-high-speed aircraft), three name an ore (copper pyrites, chalcopyrite, calamine) and two a catalyst (V₂O₅ in the contact process, Co–Th in the Fischer–Tropsch synthesis). One card.

Concept 1 of 1: Alloys, Ores and Catalysts to Know

Three lookup lists. For ores, the name often carries the metal and the anion: copper pyrites is CuFeS₂ (copper, iron and sulphur), calamine is zinc carbonate, siderite is iron carbonate. For catalysts, remember the process: contact process → V₂O₅, Haber → iron, hydrogenation of oils → nickel, Fischer–Tropsch gasoline from water gas → cobalt–thoria. For alloys, match the property to the use: nichrome resists heat (heating coils, gas turbines), stainless steel resists heat and corrosion (high-speed aircraft skin).

Definition

  • Alloys: nichrome (Ni–Cr) — heating elements, gas turbine engines; stainless steel (Fe–Cr–Ni) — outer fuselage of ultra-high-speed aircraft, utensils; cupronickel (Cu–Ni) — coins; bronze (Cu–Sn); brass (Cu–Zn).
  • Ores: copper — chalcopyrite / copper pyrites CuFeS2\text{CuFeS}_2 (Cu, Fe, S), chalcocite Cu2S\text{Cu}_2\text{S}; zinc — calamine ZnCO3\text{ZnCO}_3, zincite ZnO, zinc blende ZnS; iron — siderite FeCO3\text{FeCO}_3, limonite Fe2O3⋅xH2O\text{Fe}_2\text{O}_3\cdot x\text{H}_2\text{O}, haematite Fe2O3\text{Fe}_2\text{O}_3, magnetite Fe3O4\text{Fe}_3\text{O}_4.
  • Catalysts: contact process (SO2→SO3\text{SO}_2 \to \text{SO}_3) — V2O5\text{V}_2\text{O}_5; Haber process — Fe (Mo promoter); hydrogenation of oils — Ni; Fischer–Tropsch (gasoline from water gas) — Co–Th (cobalt–thoria); Ziegler–Natta polymerisation — TiCl4+Al(C2H5)3\text{TiCl}_4 + \text{Al(C}_2\text{H}_5)_3; Ostwald process — Pt/Rh.
MetalOresCatalyst use
CuChalcopyrite (copper pyrites) CuFeS₂; chalcocite Cu₂S—
ZnCalamine ZnCO₃; zincite ZnO; zinc blende ZnS—
FeSiderite FeCO₃; limonite; haematite Fe₂O₃; magnetite Fe₃O₄Haber process
V—V₂O₅ in the contact process
Co—Co–Th in the Fischer–Tropsch synthesis
Ni—Hydrogenation of oils; Ni–Cr is nichrome
Siderite, limonite and haematite are iron; calamine and zincite are zinc.
Practise this conceptself-check · 5 quick reps

The same idea in a real exam question:

MHT-CET · 2023 · 2nd May Shift 1 · Q100Easy

Example 1 · Transition and Inner Transition Elements · Alloys, Minerals, Ores and Catalysts

Identify elements present in copper pyrites.

Reading 'copper pyrites' as copper and sulphur only

Copper pyrites is CuFeS₂ — iron is in it too. And chalcocite (Cu₂S) is copper, while chalcopyrite is the mixed copper–iron sulphide.
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Summary — formulas & gotchas at a glance

A revision cheat-sheet for the formulas and gotchas above. Click any concept name to jump back to its full explanation.

Reference tables (1)

Alloys, Ores and Catalysts to Know6 rows
MetalOresCatalyst use
CuChalcopyrite (copper pyrites) CuFeS₂; chalcocite Cu₂S—
ZnCalamine ZnCO₃; zincite ZnO; zinc blende ZnS—
FeSiderite FeCO₃; limonite; haematite Fe₂O₃; magnetite Fe₃O₄Haber process
V—V₂O₅ in the contact process
Co—Co–Th in the Fischer–Tropsch synthesis
Ni—Hydrogenation of oils; Ni–Cr is nichrome
Siderite, limonite and haematite are iron; calamine and zincite are zinc.

Watch out for (1)

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