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Predict the modes of occurrence of the following three types of metals : (a) Highly reactive (e.g `Na`) (b) Moderately reactive (e.g `Fe`) ( c) Noble metal (e.g `Au`). |
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Answer» (i) Highly reactive : Being highly reactive in nature, it does not occur in nature in free state. In the combined form, sodium occurs as (a) Sodium chloride, `NaCl` (b) Sodium nitrate or Chile saltpetre, `NaNO_(3)` ( c) Sodium carbonate, `Na_(2) CO_(3)` (d) Borax, `Na_(2) B_(4)O_(7).10 H_(2) O`. (ii) Moderately reactive : Being moderately reactive in nature, it does not occur in nature in free state. In the combined form, iron occurs as (a) Magnetic, `Fe_(3)O_(4)` (b) Haematite, `Fe_(2)O_(3)` ( c) Limonite or hydrated ferric oxide, `Fe_(2)O_(3).3H_(2)O` (d) Siderite or spathic iron, `FeCO_(3)` ( e) Iron pyrites, `FeS_(2)` (f) Chalcopyrites, `CuFeS_(2)`. (iii) Noble metal : Being noble metal, it is found in free state in nature, e.g. `Au,Pt` etc. |
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