Uploaded October 2019 | Updated September 2026, 2 hours ago

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Cleaned iron nails are place inside a solution of copper(II) sulphate. Iron has a stronger tendency to become oxidised than copper. Iron metal is oxidised to iron(II) ions and the solution turns from blue to green-blue. Copper(II) ions are reduced to copper metal, forming an orange-brown coating on the sides of the iron nail.

Cu2+(aq) + Fe(s) = Cu(s) + Fe2+(aq) redox

Cu2+(aq) + 2e- = Cu(s) reduction
Fe(s) = Fe2+(aq) + 2e- oxidation

Thank you to Laura B. for making the video