Introduction
When an iron nail is dipped into a copper sulfate (CuSO₄) solution, a noticeable color change occurs, indicating a chemical reaction. This phenomenon showcases the principles of displacement reactions and oxidation-reduction (redox) processes.

Chemical Reaction
- The key reaction is a displacement reaction, where iron (Fe) displaces copper (Cu) from copper sulfate.
- The reaction can be represented as:
\[ \text{Fe} + \text{CuSO}_4 \rightarrow \text{FeSO}_4 + \text{Cu} \]

Color Change
- **Initial Color**: The original copper sulfate solution is blue due to the presence of Cu²⁺ ions.
- **After Dipping the Nail**: As the reaction proceeds:
- Iron ions (Fe²⁺) enter the solution, forming iron(II) sulfate (FeSO₄), which is pale green.
- Solid copper metal is deposited on the nail, leading to a decrease in the concentration of Cu²⁺ ions.

Observation
- The blue color of the solution fades and transitions to a greenish hue due to the formation of FeSO₄.
- The copper deposited on the iron nail can be seen as reddish-brown particles.

Conclusion
This experiment illustrates fundamental concepts in chemistry, specifically displacement reactions and the interplay of oxidation and reduction, highlighting the reactivity of metals.
Understanding these reactions is essential for various applications in chemistry, materials science, and engineering.