Experiment 9: Iron & Copper reactivity

Objective

Study the relative reactivity of metals like iron and copper

Materials required:

• Iron nails
• 5% Copper sulphate
• Dilute sulphuric acid
• Dropper
• Test tube holder
• Test Tubes

Procedure:

• Take the beaker and add about 20mL of water in it
• Pour about a 2gm of copper sulphate in water and shake well to dissolve it
• Add a 4-5 drops of dilute sulphuric acid to the solution by using dropper
• Drop an iron piece (nail, blade, etc.) into the solution
• After nearly half an hour observe the change in the colour of blade as well as of copper sulphate solution

Findings:

• The blue colour solution of copper sulphate first fades and then changes to green and a brown deposit is formed on the shaving blade.

Conclusions:

• Copper metal which is brown in colour is deposited on shaving blade due to its displacement from copper sulphate by iron.
• Green colour of the solution is due to the formation of iron sulphate.
• Copper sulphate (blue) + Iron (grey) → Iron sulphate (light green) + Copper (brown)

Theory:

• Different metals have different reactivities with chemical reagents. The metals that form positive ions by losing electrons more readily. A more reactive metal displaces a less reactive metal from salt solution. Such reactions are called displacement reactions.
• Aluminium is more reactive than zinc.
• Zinc is more reactive than Fe.
• Fe is more reactive than Cu.

The below table gives you an understanding of the colours exhibited by the metals and their salts: