Chemical Forums
Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: Lego on October 23, 2004, 12:55:52 PM
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Did some simple school experiments using magnesium, zinc, and tin to displace copper from copper sulphate solution - all produced copper as expected. Tried same reactions with iron(II) sulphate solution but got no iron - just a light brown precipitate. Puzzled??
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and what does this make you think?
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Well if I could think of a reasonable explanation I wouldn't have asked - both Mg & Zn should have produced Fe. The Fe displaced could have reacted at once with the water producing the precipitate BUT the Sn should not have displaced any Fe & still I got the same coloured precipitate. Which leaves me with the possiblity that the Fe(II) sulphate reacts with the water before displacement occurs forming ?? This is just guess work - I would like to know what really is happening & can't find the explanation in my chemistry books! Thanks, Lego.
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Iron (metal) reacts with water.
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Agreed, but normally very, very slowly for a piece of iron metal in cold water. Perhaps the tiny particle size produced would explain a much faster rate, but there should not have been any Fe displaced by Sn but the precipitate was formed.
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neutral solutions of FeII are unstable in water and will oxidize to FeIII and precipitate as fe(OH)3 more rapidly than in acidic solution. This is why FeII sulphate solution is typically prepared in dilute (0.1M) sulphuric acid.
Perhaps the metal is acting as a catalyst that speeds up this process.
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That might explain why I haven't seen this particular reaction described in any of my texts. Thanks for your help.