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Question
A metal X which is resistant to corrosion is produced by the electrolysis of its molten oxide whereas another metal Y which is also resistant to corrosion is produced by the reduction of its oxide with carbon. Metal X can be used in powder form in thermite welding whereas metal Y is used in making cathodes of ordinary dry cells.
- Name the metals X and Y.
- Which of the two metals is more reactive: X or Y?
- Name one ore or metal X. Also write its chemical formula.
- Name one ore of metal Y. Also write its chemical formula.
- Name one alloy of metal X and one alloy of metal Y.
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Solution
- Metal X is aluminium (Al) and metal Y is zinc (Zn). Aluminium is corrosion-resistant due to its protective oxide layer and is used in thermite welding. Zinc is also corrosion-resistant (used in galvanisation) and forms the anode (outer container) of ordinary dry cells.
- X (aluminium) is more reactive than Y (zinc). Aluminium is placed above zinc in the reactivity series.
- One ore of metal X (aluminium) is bauxite ore. The chemical formula of bauxite ore is Al2O3.2H2O.
- One ore of metal Y (zinc) is calamine ore. The chemical formula of calamine ore is ZnCO3.
- One alloy of metal X (aluminium) is magnalium, which consists of aluminium and magnesium. One alloy of metal Y (zinc) is brass, which consists of zinc and copper.
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