When a copper ion solution (Cu²⁺) is combined with a lithium solution (Li⁺), a redox reaction will occur, leading to the formation of copper metal and lithium ions.

Here's the breakdown:

* Copper ions (Cu²⁺) are more easily reduced (gain electrons) than lithium ions (Li⁺).

* Lithium ions (Li⁺) are more easily oxidized (lose electrons) than copper ions (Cu²⁺).

The reaction equation:

Cu²⁺(aq) + 2Li(s) → Cu(s) + 2Li⁺(aq)

Explanation:

* Copper ions (Cu²⁺) gain two electrons from the lithium metal, becoming copper metal (Cu).

* Lithium metal (Li) loses an electron, becoming lithium ions (Li⁺).

Observations:

* Reddish-brown copper metal will precipitate out of the solution.

* The solution will change color depending on the concentration of the remaining ions.

Important Note: This reaction is highly exothermic, meaning it releases a lot of heat. It can be quite vigorous, so it should be carried out with caution in a controlled environment.

Additional Information:

* This type of reaction is known as a displacement reaction, where a more reactive metal (lithium) displaces a less reactive metal (copper) from its solution.

* The reactivity of metals is determined by their standard reduction potential. Lithium has a much lower reduction potential than copper, indicating that it is more likely to lose electrons and be oxidized.