1.2.3. Displacement Reaction

n Take three iron nails and clean them by rubbing with sand paper. n Take two test tubes marked as (A) and (B). In each test tube, take about 10 mL copper sulphate solution. n Tie two iron nails with a thread and immerse them carefully in the copper sulphate solution in test tube B for about 20 minutes. n After 20 minutes, take out the iron nails from the copper sulphate solution. n Compare the intensity of the blue colour of copper sulphate solutions in test tubes (A) and (B). n Also, compare the colour of the iron nails dipped in the copper sulphate solution with the one kept aside.

In this activity, we are investigating what happens when iron nails are placed in a copper sulphate solution. First, we clean the nails to remove any impurities that may affect the reaction. Then, we immerse two of the nails in test tube B with the copper sulphate solution while keeping one nail aside for comparison in test tube A. After 20 minutes, we observe changes in color both in the solution and on the nails, indicating that a chemical reaction has occurred. Specifically, the blue color of the copper sulphate will fade in test tube B, and the iron nails will turn brownish due to the formation of iron sulfate.

Think of it like a game of musical chairs where iron is trying to take copper's place. The iron nails, which are like new contenders in the chair game, push out the copper from the copper sulphate solution, leading to a change in both the nails and the liquid.

Fe(s) + CuSO₄(aq) → FeSO₄(aq) + Cu(s)

The chemical equation summarizes what happens during the displacement reaction. Iron (Fe), a solid, reacts with copper sulfate (CuSO₄) in an aqueous solution. In this reaction, iron displaces copper, forming iron sulfate (FeSO₄), which remains in solution, and solid copper (Cu), which can be seen deposited on the nails.

Imagine a situation where a friend is too close to the bonfire and needs to step back. Iron is 'stepping back' from the copper sulfate solution, and copper, which was sitting in the background, is now 'coming forward' in the form of solid copper deposited on the nails.

In this reaction, iron has displaced or removed another element, copper, from copper sulphate solution. This reaction is known as displacement reaction.

A displacement reaction occurs when a more reactive metal displaces a less reactive metal from its compound. In our example, iron is more reactive than copper, so it successfully displaces copper from copper sulfate, leading to the formation of iron sulfate. Displacement reactions are key in demonstrating the reactivity series of metals, where we can see which metals can replace others in a compound.

Think of it like a competitive sports game where the stronger player (iron) can kick out the weaker player (copper) from the game (solution). This is how displacement reactions help us understand which metals are stronger in nature!