**Introduction:**

Copper sulfate solution is a blue-colored liquid that contains copper ions (Cu2+) and sulfate ions (SO42-). When an iron nail is dipped in this solution, a reaction takes place, resulting in a change in the color of the solution. This phenomenon can be explained by the principles of redox reactions and the formation of a new compound.

**Redox Reaction:**

When the iron nail is placed in the copper sulfate solution, a redox reaction occurs. Redox reactions involve the transfer of electrons between two species. In this case, the iron atoms in the nail lose electrons and are oxidized, while the copper ions in the solution gain electrons and are reduced.

**Oxidation of Iron:**

Iron in the nail is oxidized, meaning it loses electrons. The iron atoms on the surface of the nail react with the sulfate ions (SO42-) in the solution. This causes the iron atoms to lose two electrons and form iron(II) ions (Fe2+). The reaction can be represented as follows:

Fe(s) → Fe2+(aq) + 2e-

**Reduction of Copper:**

The copper ions (Cu2+) in the solution gain the electrons that were lost by the iron atoms. This reduction process results in the formation of metallic copper (Cu) on the surface of the nail. The copper atoms deposit onto the iron nail, giving it a reddish-brown appearance. The reduction reaction can be represented as follows:

Cu2+(aq) + 2e- → Cu(s)

**Formation of Copper Deposits:**

As the redox reaction proceeds, the metallic copper deposits continue to form on the iron nail. These copper deposits are visible as a reddish-brown coating on the nail's surface. The color change is due to the presence of copper atoms, which have a different electronic structure and absorb and reflect light differently compared to the copper sulfate solution.

**Conclusion:**

In summary, when an iron nail is dipped in a copper sulfate solution, a redox reaction occurs. The iron atoms on the nail's surface are oxidized to form iron(II) ions, while the copper ions in the solution are reduced to metallic copper. The deposition of copper on the iron nail gives it a reddish-brown appearance, resulting in a color change of the solution. This phenomenon can be explained by the principles of redox reactions and the formation of a new compound.