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Summary
DescriptionCorrosão de ferro por sacrifício em contacto com cobre.jpg
Português: Corrosão de um prego de ferro com fio de cobre enrolado, em meio de agar agar com ferroxil (hexacianoferrato (III) de potássio, indicador de iões ferro, e fenolftaleína, indicador de iões hidróxido). Resultados após 3 dias.
Devido à presença de cobre, o ferro é corroído mais rapidamente por sacrifício. O indicador é azul perto do ferro, o que indica libertação de iões ferro para o meio (oxidação do ferro - zona anódica) e rosa perto do cobre, o que indica a libertação de iões hidróxido para o meio (redução do oxigénio - zona catódica).
English: Corrosion of a iron nail with a coiled copper wire, in agar-agar medium with ferroxyl indicator solution (potassium hexacyanoferrate(III), indicator of iron ions, and phenolphthalein, indicator of hydroxide ions). Results obtained after 3 days.
Due to presence of copper, the iron is corroded faster because it is the sacrificial metal in this case. The blue color near the iron indicates the presence of iron ions in the medium (iron oxidation - anodic zone) and pink near the copper indicates the presence of hydroxide ions in the medium (oxygen reduction - cathodic zone).
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