a beaker contains and acidified copper …

The process of depositing a thin layer of desired metal over a metal object with the help of electric current is called electroplating. The purpose of electroplating is to protect the metal objects from corrosion or to make the metal objects look more attractive. The metal objects are usually electroplated with chromium, tin, nickel, silver, gold or copper objects.

Take 250 ml of distilled water in a clean beaker and dissolve two teaspoon full of copper sulphate in it. This will give us a blue coloured copper solution. Add a few drops of dilute sulphuric acid to copper sulphate solution to make it more conducting. Take a copper plate and a door key made of iron. Clean copper plates and the iron key by rubbing it with sand paper. Now rinse them with water and dry them.  Immerse the cleaned copper plate in copper sulphate solution in the beaker. Connect the copper plate to the positive terminal of a battery through a switch. This copper plate becomes the positive terminal. Immerse the cleaned iron key in copper sulphate solution and connect it to the negative terminal of the battery so that it becomes the negative electrode.  Allow the current to pass for about 15 minutes. Now remove the electrodes from the solution and observe. We will find that the copper plate has dissolved a little and the iron key has got a reddish layer of copper metal all over its surface. Thus, the iron key has become electroplated with copper. The solution remains unchanged.