Question

Why does the color of copper sulphate change when an iron nail is kept in it? Justify your answer.

Answer 1

Diagram of Event

The reaction of copper sulfate and iron nail

• In a reactivity series, the position of iron is above the position of Copper which means the reactivity of iron is greater than that of Copper.
• So, when the iron and Copper sulfate reacts, the iron replaces the copper from it and forms the Ferrous sulfate, and due to this displacement, the color of the solution changes from blue to pale green.
• $\underset{\left(\mathrm{Copper}\mathrm{Sulfate}\right)}{{\mathrm{CuSO}}_4\left(\mathrm{s}\right)}+\underset{\left(\mathrm{Iron}\right)}{\mathrm{Fe}\left(\mathrm{s}\right)}\to \underset{\left(\mathrm{Ferrous}\mathrm{Sulfate}\right)}{{\mathrm{FeSO}}_4\left(\mathrm{aq}\right)}+\underset{\left(\mathrm{Copper}\right)}{\mathrm{Cu}\left(\mathrm{s}\right)}$