Apparatus: Copper wire, iron nail, beaker or big test tube, etc.
Chemicals: Aqueous solutions of ferrous sulphate and copper sulphate.
Procedure: i. Take a clean copper wire and a clean iron nail.
ii. Dip the copper wire in ferrous sulphate solution and the iron nail in copper sulphate solution.
iii . Keep on observing continually at a fixed interval of time.
In which test tube a reaction has taken place?

Explanation

The reaction occurs in the test tube in which iron nail is dipped in copper sulphate solution