2003 發問於 科學及數學化學 · 1 十年前

rusting question

http://img225.imageshack.us/img225/5959/111fc6.jpg

唔明點解會有pink colour

唔好答我因為alkaline

1 個解答

評分
  • 1 十年前
    最愛解答

    Fe is more reactive (at a higher position in electrochemical series) than Cu. Thus, Fe is oxidized to Fe2+ and releases electrons.

    Fe(s) → Fe2+(aq) + 2e-(aq)

    Electrons flows from Fe to Cu. In the presence of water, oxygen in water accepts electrons and is reduced to give OH-(aq) ions.

    2H2O(l) + O2(g/aq) + 4e- → 4OH-(aq)

    The OH-(aq) formed will change the phenolphthalein indicator to pink.

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