Answer:
sulfate
Step-by-step explanation:
The phenomenon you're referring to is likely related to the demonstration known as the "Needle in a Copper Solution" experiment. In this experiment, a copper sulfate solution is used, and when an iron needle is inserted into the solution, the needle may appear to move or "jump" on its own.
The key chemical reaction responsible for this movement involves the displacement of copper ions from the copper sulfate solution by iron. The iron needle acts as a more reactive metal compared to copper, so it displaces copper ions from the solution, forming iron sulfate and allowing copper to be deposited onto the surface of the needle. This deposition of copper creates a thin layer of copper on the iron needle, causing the needle to appear to move or "jump" due to changes in buoyancy and surface tension.
Therefore, the chemical involved here is copper sulfate (CuSO4), which is dissolved in the solution, and the key metal involved is iron, which is present in the form of the needle. The reaction between iron and copper sulfate results in the movement of the needle in the solution.